How to make an incendiary laser at home. How to make a laser that burns

In every house there is an old worn-out technique. Someone throws it in a landfill, and some craftsmen try to use it for some homemade inventions. So the old laser pointer can be put to good use - it is possible to make a laser cutter with your own hands.

To make a real laser from a harmless trinket, you need to prepare the following items:

laser pointer;
flashlight with rechargeable batteries;
old, maybe not a working CD / DVD-RW writer. The main thing is that he has a drive with a working laser;
a set of screwdrivers and a soldering iron. It is better to use a branded cutter, but in the absence of a regular one, it may also work.

Making a laser cutter

First you need to remove the laser cutter from the drive. This work is not difficult, but you will have to be patient and pay maximum attention. Since it contains a large number of wires, their structure is the same. When choosing a drive, it is important to consider the presence of a writing option, since it is in this model that a laser can make recordings. Recording is done by evaporating a thin layer of metal from the disc itself. In the case when the laser works for reading, it is used at half strength, highlighting the disk.

When dismantling the top fasteners, you can find a carriage with a laser located in it, which is able to move in two directions. It should be carefully removed by unscrewing, there are a large number of detachable devices and screws that are important to carefully remove. For further work, a red diode is needed, with which the burning is carried out. To remove it, you will need a soldering iron, and you also need to carefully remove the fasteners. It is important to note that an indispensable part for the manufacture of a laser cutter cannot be shaken and dropped, therefore, it is recommended to be careful when removing the laser diode.

How the main element of the future laser model will be removed, you need to carefully weigh everything and figure out where to put it and how to connect the power supply to it, since the writing laser diode needs much more current than the diode from the laser pointer, and in this case you can use several ways.

Next, the diode in the pointer is replaced. To create a powerful laser pointer, the native diode must be removed, in its place it is necessary to install a similar one from the CD / DVD-RW drive. The pointer is disassembled in sequence. It must be untwisted and divided into two parts, on top is the part that needs to be replaced. The old diode is removed and the required diode is installed in its place, which can be fixed with glue. There are cases when it can be difficult to remove the old diode, in this situation you can use a knife and shake the pointer a little.

The next step will be the manufacture of a new case. So that the future laser can be conveniently used, connect power to it and to give it an impressive look, you can use the flashlight case. The converted upper part of the laser pointer is installed into a flashlight and power is supplied to it from rechargeable batteries, which is connected to the diode. It is important not to reverse the polarity of the power supply. Before assembling the flashlight, the glass and parts of the pointer must be removed, as it will not conduct the direct path of the laser beam well.

The last step is preparation for use. Before connecting, it is necessary to check the strength of the laser fixing, the correct connection of the polarity of the wires and whether the laser is level.

After completing these simple steps, the laser cutter is ready for use. Such a laser can be used to burn through paper, polyethylene, to ignite matches. The scope can be extensive, everything will depend on the imagination.

Additional points

You can make a more powerful laser. For its manufacture you will need:

DVD-RW drive, can be in non-working condition;
capacitors 100 pF and 100 mF;
resistor 2-5 ohm;
three rechargeable batteries;
wires with a soldering iron;
collimator;
steel LED flashlight.

This is the uncomplicated kit that comes with the assembly of the driver, which, using the board, will bring the laser cutter to the required power. The current source cannot be connected directly to the diode, as it will instantly deteriorate. It is also important to consider that the laser diode must be powered by current, not voltage.

The collimator is a housing equipped with a lens, thanks to which all the rays converge into one narrow beam. Such devices are purchased at radio parts stores. They are convenient in that they already have a place for installing a laser diode, and as for the cost, it is quite small, only 200-500 rubles.

You can, of course, use a case from a pointer, but it will be difficult to attach a laser in it. Such models are made of plastic material, and this will lead to heating of the case, and it will not be cooled enough.

The manufacturing principle is similar to the previous one, since in this case a laser diode from a DVD-RW drive is also used.

During manufacture, antistatic wrist straps must be used.

This is necessary to remove static from the laser diode, it is very sensitive. In the absence of bracelets, you can get by with improvised means - you can wind a thin wire around the diode. Next comes the driver.

Before assembling the entire device, the operation of the driver is checked. In this case, it is necessary to connect a non-working or second diode and measure the strength of the supplied current with a multimeter. Given the speed of the current, it is important to select its strength according to the norms. For many models, a current of 300-350 mA is applicable, and for faster ones, 500 mA can be used, but a completely different driver must be used for this.

Of course, any non-professional technician can assemble such a laser, but nevertheless, for beauty and convenience, it is most reasonable to build such a device in a more aesthetic case, and which one to use can be chosen for every taste. It will be most practical to assemble it in the case of an LED flashlight, since its dimensions are compact, only 10x4 cm. But still, you do not need to carry such a device in your pocket, as the relevant authorities may make claims. Such a device is best stored in a special case to avoid dusting the lens.

Sometimes you can make something really incredible and useful from unnecessary things stored at home. Do you have an old DVD-RW (writer) drive lying around at home? We will show you how to make a powerful laser at home by borrowing elements from it.

Safety

The device we end up with is not a harmless toy! Before you make a laser, take care of your safety: hitting the beam in the eyes is detrimental to the retina, especially if the invention is powerful. Therefore, we advise you to carry out all work in special protective glasses that will save your eyesight if something goes wrong and you accidentally direct the laser beam into yourself or a friend's eyes.

When using the laser in the future, remember these simple safety precautions:

Do not aim the laser beam at flammable or explosive objects.
Do not shine on reflective surfaces (glasses, mirrors).
Even a laser beam fired from a distance of up to 100 m poses a danger to the human and animal retinas.

Working with the laser module

The main thing we need is a burner. Note that the higher the write speed, the more powerful our DVD laser will be. It goes without saying that after removing the laser module, the equipment will become inoperative, so disassemble only such a device that you no longer need.

And now we start:

The first part of our work is over. Let's move on to the next important step.

Assembling the device circuit

We need a circuit in order to control the power of our device. Otherwise, it will simply burn out on the first use. You will see the drawing for the laser below.

For our device, hanging mounting is quite suitable. And now let's move on to providing power to a do-it-yourself laser.

Device power supply

We will need a minimum of 3.7 V. Old batteries from mobile phones, penlight batteries can provide this. It is only necessary to connect them in parallel with each other. To check the operation of the device or a stationary laser pointer, a stabilization power supply is suitable.

At this stage, you can already test the operation of the device. Point it at the wall, floor and turn on the power. You should see a bunch of bright reddish color. In the dark, it looks like a powerful infrared flashlight.

You can see that while the glow is far from the laser: the beam is too wide; he asks to be focused. This is what we will do next.

Lens for focusing the laser beam

To adjust the focal length, you can get by with a lens borrowed from the same DVD-RW drive.

Now reconnect the power to the device, directing its light to any surface through this lens. Happened? Then we move on to the final stage of work - placing all the elements in a rigid case.

Case manufacturing

Many, advising how to make a laser, say that the easiest way is to place the module in a case from a small flashlight or a Chinese laser pointer. Where, by the way, there is already a lens. But let's analyze the situation, if neither one nor the other was at hand.

As an option - place the elements in an aluminum profile. It is easily sawn with a hacksaw, modeled with pliers. You can also add a small finger battery here. How to do this, the photo below will guide you.

Be sure to insulate all contacts. The next step is fixing the lens in the housing. It is easiest to mount it on plasticine - so you can adjust the most successful position. In some cases, a better effect is achieved if you turn the lens towards the laser diode with the convex side.

Turn on the laser and adjust the beam clarity. Once you are satisfied with the results, lock the lens into the housing. Then close it entirely, for example, tightly wrapping it with electrical tape.

How to make a laser: an alternative way

We will offer you another, somewhat different way to make a homemade powerful laser. You will need the following:

DVD-RW drive with a recording speed of 16x or more.
Three finger batteries.
Capacitors 100 mF and 100 pF.
Resistor from 2 to 5 ohms.
Wires.
Soldering iron.
Laser pointer (or any other collimator - this is the name of the module with a lens).
LED steel lantern.

Now let's see how to make a laser using this method:

Remove the laser module located in the device carriage from the drive in the way already described. Remember to protect it from static electricity by wrapping the outputs with thin wire or wearing an antistatic wrist strap.
According to the above scheme, solder the driver - the board that will bring our homemade product to the desired power. Pay great attention to polarity so as not to damage the sensitive laser diode.
In this step, we will test the performance of the newly built driver. If the laser module is from a model with a speed of 16x, then a current of 300-350 mA is enough for it. If higher (up to 22x), then stop at 500mA.
After you have verified that the driver is suitable, it must be placed in the case. It can be either a base from a Chinese laser pointer with a lens already mounted, or a more suitable housing from an LED flashlight.

Laser testing

And here is what you were interested in how to make a laser for. Let's move on to practical testing of the device. In no case do not spend it at home - only on the street, away from fire and explosive objects, buildings, dead wood, heaps of garbage, etc. For experiments, we need paper, plastic, the same electrical tape, plywood.

So let's start:

Place a sheet of paper on asphalt, stone, brick. Aim an already well-focused laser beam at it. You will see that after a while the leaf will begin to smoke, and then it will completely light up.
Now let's move on to plastic - it will also begin to smoke from exposure to a laser beam. We do not recommend conducting such experiments for a long time: the combustion products of this material are very toxic.
The most interesting experience is with plywood, a flat plank. A focused laser can burn a certain inscription, drawing on it.

A home laser is, of course, a delicate work and a capricious invention. Therefore, it is quite possible that your craft will soon fail, as certain storage and operating conditions are important for it, which cannot be provided at home. The most powerful lasers, which can easily cut metal, can only be obtained in specialized laboratories; naturally, they are not available to amateurs. However, a conventional device is also very dangerous - directed from a long distance into the eyes of a person or animal, close to a flammable object.

Man has learned many technical inventions by observing natural phenomena, analyzing them and applying the acquired knowledge in the surrounding reality. So man got the ability to kindle a fire, created a wheel, learned to generate electricity, got control over a nuclear reaction.

Unlike all these inventions, the laser has no analogues in nature. Its emergence was associated solely with theoretical assumptions within the framework of emerging quantum physics. The existence of the principle that formed the basis of the laser was predicted at the beginning of the 20th century by the greatest scientist Albert Einstein.

The word "laser" appeared as a result of the reduction of five words describing the essence of the physical process to the first letters. In the Russian version, this process is called "amplification of light with the help of stimulated emission."

According to the principle of its operation, the laser is a quantum generator of photons. The essence of the phenomenon underlying it is that under the action of energy in the form of a photon, an atom emits another photon, which is identical to the first one in the direction of motion, its phase and polarization. As a result, the emitted light is amplified.

This phenomenon is impossible under conditions of thermodynamic equilibrium. Various methods are used to create induced radiation: electrical, chemical, gas, and others. Lasers used in the home (laser disk drives, laser printers) use semiconductor method stimulation of radiation under the action of an electric current.

The principle of operation is the passage of an air flow through the heater into the hot air gun tube and, having reached the set temperatures, it enters the part to be soldered through special nozzles.

In the event of a malfunction, the welding inverter can be repaired by hand. You can read repair tips.

In addition, a necessary component of any full-fledged laser is optical resonator, the function of which is to amplify the beam of light by reflecting it multiple times. For this purpose, mirrors are used in laser systems.

It should be said that creating a real powerful laser with your own hands at home is unrealistic. For this, it is necessary to have special knowledge, carry out complex calculations, and have a good material and technical base.

For example, laser machines that can cut metal are extremely hot and require extreme cooling measures, including the use of liquid nitrogen. In addition, devices based on the quantum principle are extremely capricious, require the finest tuning and do not tolerate even the slightest deviation from the required parameters.

Required Components for Assembly

To assemble a laser circuit with your own hands, you will need:

Rewritable DVD-ROM (RW). It incorporates a red laser diode with a power of 300 mW. You can use laser diodes from BLU-RAY-ROM-RW - they emit violet light with a power of 150 mW. For our purposes, the best ROMs are those with faster write speeds: they are more powerful.
Pulse NCP1529. The converter outputs a current of 1A, stabilizes the voltage in the range of 0.9-3.9V. These indicators are ideal for our laser diode, which requires a constant voltage of 3V.
Collimator for obtaining an even beam of light. Now on sale are numerous laser modules from various manufacturers, including collimators.
Output lens from ROM.
Housing, for example, from a laser pointer or flashlight.
Wires.
Batteries 3.6 V.

To connect the parts you will need. In addition, you will need a screwdriver and tweezers.

How to make a laser from a disk drive?

The procedure for assembling a simple laser consists of the following steps.

It's not at all difficult to do. The difference is in the number of contacts. In a pass-through switch, unlike a simple one, there are three contacts instead of two.

In this way, the simplest laser can be assembled. What can such a handicraft "light amplifier" do:

Light a match from a distance.
Melt plastic bags and thin paper.
Emit a beam at a distance of more than 100 meters.

Such a laser is dangerous: it will not burn skin or clothing, but it can damage the eyes.
Therefore, you need to use such a device carefully: do not shine it on reflective surfaces (mirrors, glasses, reflectors) and, in general, be extremely careful - the beam can cause harm if it hits the eye even from a distance of one hundred meters.

Do-it-yourself laser on video

Turn your MiniMag laser pointer into a cutting laser with a DVD burner emitter! This 245mW laser is very powerful and is the perfect size for your MiniMag! Watch the attached video. PLEASE NOTE: you can do this yourself NOT WITH ALL CDRW-DVD cutter diodes!

Warning: WARNING! As you know, lasers can be dangerous. Never point at a living creature! This is not a toy and should not be treated like a regular laser pointer. In other words, don't use it for presentations or animal play, don't let kids play with it. This device should be in the hands of a reasonable person who is aware of and responsible for the potential danger that the sign represents.

Step 1 - What you need...

You will need the following:

1. 16X DVD cutter. I used an LG drive.

Step 2 - And...

2. The MiniMag laser pointer can be purchased at any hardware, sports or household store.

3. AixiZ Case with AixiZ for $4.50

4. Small screwdrivers (watch), clerical knife, metal shears, drill, round file and other small tools.

step 3 - Remove the laser diode from the DVD drive

Remove the screws from the DVD drive, remove the cover. Under it you will find the laser carriage drive assembly.

step 4 - Take out the laser diode...

although DVD drives are different, each has two rails on which the laser carriage moves. Remove the screws, release the guides and remove the carriage. Disconnect connectors and flat ribbon cables.

Step 5 - Let's move on...

After removing the carriage from the drive, start disassembling the device by unscrewing the screws. There will be a lot of small screws, so please be patient. Disconnect the cables from the carriage. There may be two diodes, one for reading the disc (infrared diode) and the actual red diode, with which the burning is carried out. You need a second one. A printed circuit board is attached to the red diode with the help of three screws. Use a soldering iron to CAREFULLY remove the 3 screws. You can test the diode using two AA batteries, taking into account the polarity. You will have to pull the diode out of the case, which will vary depending on the drive. The laser diode is a very fragile part, so be extremely careful.

Step 6 - Laser diode in a new guise!

This is what your diode should look like after "freeing".

Step 7 - Preparing the AixiZ Case…

Remove the sticker from the AixiZ case and unroll the case into the top and bottom. Inside the top is a laser diode (5 mW), which we will replace. I used an X-Acto knife and after two light strokes, the native diode came out. In fact, with such actions, the diode can be damaged, but I have previously managed to avoid this. Using a very small screwdriver, knocked out the emitter.

Step 8 - Assembling the Case...

I used some hot glue and carefully installed the new DVD diode in the AixiZ case. With pliers, I SLOWLY pressed the edges of the diode towards the case until it was flush.

Step 9 - Install it in MiniMag

After the two wires are soldered to the positive and negative terminals of the diode, it will be possible to install the device in the MiniMag. After disassembling the MiniMag (remove the cap, reflector, lens and emitter) you will need to enlarge the MiniMag reflector using a round file or a drill or both.

step 10 - last step

Remove the batteries from the MiniMag and after checking the polarity, carefully place the DVD laser case on top of the MiniMag where the emitter was previously. Assemble the top of the MiniMag body, attach the reflector. You won't need a plastic MiniMag lens.

Make sure the polarity of the diode is correct before you install it and connect the power! You may need to shorten the wires and adjust the beam focus.

step 11 - measure seven times

Replace the batteries (AA) and screw on the top of the MiniMag, including your new laser pointer! Attention!! Laser diodes are dangerous, so do not point the beam at people or animals.

]Book

Name
author: collective
Format: Mixed
Size: 10.31 Mb
Quality: Excellent
Language: Russian
The year of publishing: 2008

Like in a science fiction movie - you pull the trigger and the ball explodes! Learn how to make such a laser!
You can make such a laser yourself, at home from a DVD drive - not necessarily a working one. There is nothing complicated!
Lights matches, pops balloons, cuts bags and duct tape, and more
They can also burst a balloon or a light bulb in the house opposite
In the archive - a video with a laser in action and a detailed Russian instruction with pictures on how to make it!

Each of us held a laser pointer in our hands. Despite the decorativeness of the application, it contains a real laser, assembled on the basis of a semiconductor diode. The same elements are installed on laser levels and.

The next popular semiconductor-based product is your computer's DVD burner. It has a more powerful laser diode with thermal destructive power.

This allows you to burn a disc layer, putting tracks with digital information on it.

How does a semiconductor laser work?

Devices of this type are inexpensive to manufacture, the design is quite massive. The principle of laser (semiconductor) diodes is based on the use of the classic p-n junction. Such a transition works, as in conventional LEDs.

The difference in the organization of radiation: LEDs emit "spontaneously", and laser diodes "forced".

The general principle of the formation of the so-called "population" of quantum radiation is carried out without mirrors. The edges of the crystal are cleaved off mechanically, providing the effect of refraction at the ends, akin to a mirror surface.

To obtain different types of radiation, a “homojunction” can be used, when both semiconductors are the same, or a “heterojunction”, with different junction materials.

The laser diode itself is an affordable radio component. You can buy it in stores selling radio components, or you can remove it from an old DVD-R (DVD-RW) drive.

Important! Even a simple laser used in light pointers can seriously damage the retina.

More powerful installations, with a burning beam, can deprive of vision or cause burns to the skin. Therefore, when working with such devices, be extremely careful.

With such a diode at your disposal, you can easily make a powerful laser with your own hands. In fact, the product may be completely free, or it will cost you ridiculous money.

Do-it-yourself laser from a DVD drive

First, you need to get the drive itself. It can be removed from an old computer or purchased at a flea market for a symbolic cost.

Information: The higher the declared write speed, the more powerful the burn laser used in the drive.

Having removed the case, and having disconnected the control cables, we dismantle the writing head together with the carriage.

To remove the laser diode:

We connect the legs of the diode to each other with a wire (shunt). When dismantled, static electricity may accumulate and the diode may fail.
Remove the aluminum heatsink. It is quite fragile, has a mount, structurally “sharpened” for a specific DVD drive, and is not needed for further operation. Just bite the radiator with wire cutters (without damaging the diode)
Solder the diode, release the legs from the shunt.

The element looks like this:

The next important element is the power supply circuit of the laser. Using the power supply from the DVD drive will not work. It is integrated into the overall control scheme, it is technically impossible to extract it from there. Therefore, we make the power circuit ourselves.

There is a temptation to simply connect 5 volts with a limiting resistor, and not bother with the circuit. This is the wrong approach, since any LEDs (including laser ones) are powered not by voltage, but by current. Accordingly, a current stabilizer is needed. The most affordable option is to use the LM317 chip.

The output resistor R1 is selected in accordance with the power supply current of the laser diode. In this circuit, the current should correspond to 200 mA.

You can assemble a laser with your own hands in a case from a light pointer, or purchase a ready-made laser module in electronics stores or on Chinese sites (for example, Ali Express).

The advantage of this solution is that you get a ready-made adjustable lens in the kit. The power supply circuit (driver) fits easily into the module case.

If you decide to make the case yourself, from some metal tube, you can use a standard lens from the same DVD drive. Only it will be necessary to come up with a method of attachment, and the possibility of adjusting the focus.

Important! Focusing the beam is necessary for any design. It can be parallel (if you need range) or conical (if you need to get a concentrated thermal spot).

A lens complete with a regulating device is called a collimator.

To properly connect the laser from the DVD drive, you need a pin diagram. You can trace the negative and positive wires by markings on the circuit board. This must be done before dismantling the diode. If this is not possible, use a typical hint:

The negative contact has an electrical connection with the body of the diode. It won't be difficult to find him. Regarding the minus located below, the positive contact will be on the right.

If you have a three-pronged laser diode (and most of them are), there will be either an unused pin on the left or a photodiode connection. This happens if both the burning and reading element are located in the same housing.

The main body is selected based on the size of the batteries or accumulators that you plan to use. Carefully attach your homemade laser module to it, and the device is ready for use.

With the help of such a tool, you can engrave, burn wood, cut fusible materials (fabric, cardboard, felt, foam, etc.).

How to make an even more powerful laser?

If you need a cutter for wood or plastic, the power of a standard diode from a DVD drive is not enough. You will either need a ready-made diode with a power of 500-800 mW, or you will have to spend a lot of time looking for suitable DVD drives. In some LG and SONY models, laser diodes with a power of 250-300 mW are installed.

The main thing is that such technologies are available for self-production.

Step-by-step video instruction telling how to make a laser from a DVD drive with your own hands

Many of you have probably heard that it is quite possible to make a laser pointer or even a cutting beam at home using simple tools at hand, but few people know how to make a laser yourself. Before you start working on it, be sure to familiarize yourself with the safety precautions.

Laser Safety Rules

Improper use of the beam, especially high power, can result in damage to property, as well as severe harm to your health or the health of bystanders. Therefore, before testing your own made copy, remember the following rules:

Make sure there are no animals or children in the testing room.
Never point the beam at animals or people.
Use protective goggles, such as goggles used for welding.
Remember that even a reflected beam can harm your eyesight. Never shine a laser into your eyes.
Do not use the laser to ignite objects while indoors.

The simplest laser from a computer mouse

If you need a laser just for fun, it's enough to know how to make a laser at home from a mouse. Its power will be quite insignificant, but it will not be difficult to make it. All you need is a computer mouse, a small soldering iron, batteries, wires and a shutdown switch.

First, the mouse must be disassembled. It is important not to break them out, but to carefully unwind and remove them in order. Top cover first, then bottom cover. Next, using a soldering iron, you need to remove the mouse laser from the board and solder new wires to it. Now it remains to connect them to the shutdown toggle switch and connect the wires to the battery contacts. Batteries can be used of any type: both finger-type and so-called pancakes.

Thus, the simplest laser is ready.

If a weak beam is not enough for you, and you are interested in how to make a laser at home from improvised means with a sufficiently high power, then you should try a more complicated way to make it using a DVD-RW drive.

For work you will need:

DVD-RW drive (recording speed must be at least 16x);
AAA battery, 3 pcs.;
resistor (from two to five ohms);
collimator (you can replace it with a part from a cheap Chinese laser pointer);
capacitors 100 pF and 100 mF;
steel LED lantern;
wires and soldering iron.

Work progress:

The first thing we need is a laser diode. It is located in the DVD-RW drive carriage. It has a larger heatsink than a conventional infrared diode. But be careful, this part is very fragile. While the diode is not installed, it is best to wire its lead, as it is too sensitive to static voltage. Pay special attention to polarity. If the power supply is incorrect, the diode will immediately fail.

Connect the parts as follows: battery, on / off button, resistor, capacitors, laser diode. When the performance of the design has been verified, it remains only to come up with a convenient case for the laser. For these purposes, a steel case from a conventional flashlight is quite suitable. Do not forget also about the collimator, because it is he who turns the radiation into a thin beam.

Now that you know how to make a laser at home, remember to follow safety precautions, store it in a special case and do not carry it with you, as law enforcement agencies may make claims about this.

Watch the video: Laser from a DVD drive at home and with your own hands

Today we will talk about how to make your own powerful green or blue laser at home from improvised materials with your own hands. We will also consider drawings, diagrams and the device of home-made laser pointers with an ignition beam and a range of up to 20 km.

The basis of the laser device is an optical quantum generator, which, using electrical, thermal, chemical or other energy, produces a laser beam.

The operation of a laser is based on the phenomenon of stimulated (induced) radiation. Laser radiation can be continuous, with a constant power, or pulsed, reaching extremely high peak powers. The essence of the phenomenon is that an excited atom is able to emit a photon under the influence of another photon without its absorption, if the energy of the latter is equal to the difference in the energies of the levels of the atom before and after the radiation. In this case, the emitted photon is coherent to the photon that caused the radiation, that is, it is its exact copy. This is how the light is amplified. This phenomenon differs from spontaneous emission, in which the emitted photons have random directions of propagation, polarization and phase.
The probability that a random photon will cause stimulated emission of an excited atom is exactly equal to the probability of absorption of this photon by an atom in an unexcited state. Therefore, to amplify light, it is necessary that there be more excited atoms in the medium than unexcited ones. In the state of equilibrium, this condition is not satisfied, therefore, various systems for pumping the laser active medium (optical, electrical, chemical, etc.) are used. In some schemes, the working element of the laser is used as an optical amplifier for radiation from another source.

There is no external photon flux in a quantum generator; the inverse population is created inside it with the help of various pump sources. Depending on the sources, there are various pumping methods:
optical - powerful flash lamp;
gas discharge in the working substance (active medium);
injection (transfer) of current carriers in a semiconductor in the zone
rn transitions;
electronic excitation (vacuum irradiation of a pure semiconductor by a stream of electrons);
thermal (heating the gas with its subsequent rapid cooling;
chemical (using the energy of chemical reactions) and some others.

The primary source of generation is the process of spontaneous emission, therefore, to ensure the continuity of photon generations, it is necessary to have a positive feedback, due to which the emitted photons cause subsequent acts of stimulated emission. To do this, the laser active medium is placed in an optical resonator. In the simplest case, it consists of two mirrors, one of which is translucent - the laser beam partially exits the resonator through it.

Reflecting from the mirrors, the radiation beam repeatedly passes through the resonator, causing induced transitions in it. The radiation can be either continuous or pulsed. At the same time, using various devices for quickly turning off and on feedback and thereby reducing the pulse period, it is possible to create conditions for generating radiation of very high power - these are the so-called giant pulses. This mode of laser operation is called Q-switched mode.
The laser beam is a coherent, monochrome, polarized narrow beam of light. In a word, this is a beam of light emitted not only by synchronous sources, but also in a very narrow range, and directed. A sort of extremely concentrated luminous flux.

The radiation generated by the laser is monochromatic, the probability of emitting a photon of a certain wavelength is greater than that of a closely spaced one associated with the broadening of the spectral line, and the probability of induced transitions at this frequency also has a maximum. Therefore, gradually in the process of generation, photons of a given wavelength will dominate over all other photons. In addition, due to the special arrangement of mirrors, only those photons that propagate in a direction parallel to the optical axis of the resonator at a small distance from it are stored in the laser beam, the rest of the photons quickly leave the resonator volume. Thus, the laser beam has a very small angle of divergence. Finally, the laser beam has a strictly defined polarization. To do this, various polarizers are introduced into the resonator, for example, they can be flat glass plates installed at the Brewster angle to the direction of propagation of the laser beam.

What working fluid is used in the laser depends on its working wavelength, as well as other properties. The working body is "pumped" with energy to obtain the effect of electron population inversion, which causes stimulated emission of photons and the effect of optical amplification. The simplest form of an optical resonator is two parallel mirrors (there may also be four or more) located around the working body of the laser. The stimulated radiation of the working body is reflected back by the mirrors and again amplified. Until the moment of exit to the outside, the wave can be reflected many times.

So, let us briefly formulate the conditions necessary to create a source of coherent light:

you need a working substance with an inverse population. Only then it is possible to obtain amplification of light due to forced transitions;
the working substance should be placed between the mirrors that provide feedback;
the gain given by the working substance, which means that the number of excited atoms or molecules in the working substance must be greater than the threshold value, which depends on the reflection coefficient of the output mirror.

The following types of working bodies can be used in the design of lasers:

Liquid. It is used as a working fluid, for example, in dye lasers. The composition includes an organic solvent (methanol, ethanol or ethylene glycol), in which chemical dyes (coumarin or rhodamine) are dissolved. The operating wavelength of liquid lasers is determined by the configuration of the dye molecules used.

Gases. In particular, carbon dioxide, argon, krypton, or gas mixtures, as in helium-neon lasers. "Pumping" the energy of these lasers is most often carried out with the help of electrical discharges.
Solids (crystals and glasses). The solid material of such working bodies is activated (alloyed) by adding a small amount of chromium, neodymium, erbium or titanium ions. The following crystals are commonly used: yttrium aluminum garnet, yttrium lithium fluoride, sapphire (aluminum oxide), and silicate glass. Solid state lasers are usually "pumped" with a flash lamp or other laser.

Semiconductors. A material in which the transition of electrons between energy levels can be accompanied by radiation. Semiconductor lasers are very compact, "pumped" with electric current, which allows them to be used in consumer devices such as CD players.

To turn the amplifier into a generator, you need to organize feedback. In lasers, it is achieved by placing the active substance between reflecting surfaces (mirrors), which form the so-called "open resonator" due to the fact that part of the energy emitted by the active substance is reflected from the mirrors and again returns to the active substance.

Optical cavities of various types are used in the Laser - with flat mirrors, spherical, combinations of flat and spherical, etc. In optical cavities providing feedback in the Laser, only certain certain types of electromagnetic field oscillations, which are called natural oscillations or modes of the resonator, can be excited.

Modes are characterized by frequency and shape, i.e., by the spatial distribution of oscillations. In a resonator with flat mirrors, the types of oscillations corresponding to plane waves propagating along the axis of the resonator are predominantly excited. A system of two parallel mirrors resonates only at certain frequencies - and also performs in the laser the role that an oscillatory circuit plays in conventional low-frequency generators.

The use of an open resonator (rather than a closed one - a closed metal cavity - characteristic of the microwave range) is fundamental, since in the optical range a resonator with dimensions L = ? (L is the characteristic size of the resonator,? is the wavelength) simply cannot be made, and for L >> ? a closed resonator loses its resonant properties as the number of possible modes of oscillation becomes so large that they overlap.

The absence of side walls significantly reduces the number of possible types of oscillations (modes) due to the fact that waves propagating at an angle to the resonator axis quickly go beyond its limits, and makes it possible to preserve the resonant properties of the resonator at L >> ?. However, the resonator in the laser not only provides feedback by returning the radiation reflected from the mirrors to the active substance, but also determines the laser radiation spectrum, its energy characteristics, and the radiation directivity.
In the simplest approximation of a plane wave, the resonance condition in a resonator with flat mirrors is that an integer number of half-waves fit along the length of the resonator: L=q(?/2) (q is an integer), which leads to an expression for the oscillation type frequency with the index q: ?q=q(C/2L). As a result, the emission spectrum of L., as a rule, is a set of narrow spectral lines, the intervals between which are the same and equal to c / 2L. The number of lines (components) for a given length L depends on the properties of the active medium, i.e., on the spectrum of spontaneous emission at the quantum transition used, and can reach several tens and hundreds. Under certain conditions, it turns out to be possible to isolate one spectral component, i.e., to implement a single-mode generation regime. The spectral width of each of the components is determined by the energy losses in the resonator and, first of all, by the transmission and absorption of light by the mirrors.

The frequency profile of the gain in the working medium (it is determined by the width and shape of the line of the working medium) and the set of natural frequencies of the open resonator. For open resonators with a high quality factor used in lasers, the cavity bandwidth ??p, which determines the width of the resonance curves of individual modes, and even the distance between adjacent modes ??h, turn out to be smaller than the gain linewidth ??h, and even in gas lasers, where line broadening is minimal. Therefore, several types of resonator oscillations fall into the amplification circuit.

Thus, the laser does not necessarily generate at one frequency; more often, on the contrary, generation occurs simultaneously at several types of oscillations, for which gain? more losses in the resonator. In order for the laser to operate at one frequency (in the single-frequency mode), it is usually necessary to take special measures (for example, increase the losses, as shown in Figure 3) or change the distance between the mirrors so that only one fashion. Since in optics, as noted above, ?h > ?p and the generation frequency in a laser is determined mainly by the resonator frequency, it is necessary to stabilize the resonator in order to keep the generation frequency stable. So, if the gain in the working substance covers the losses in the resonator for certain types of oscillations, generation occurs on them. The seed for its occurrence, as in any generator, is noise, which is spontaneous emission in lasers.
In order for the active medium to emit coherent monochromatic light, it is necessary to introduce feedback, i.e., send part of the light flux emitted by this medium back into the medium for stimulated emission. Positive feedback is carried out using optical cavities, which in the elementary version are two coaxial (parallel and along one axis) mirrors, one of which is translucent, and the other is "deaf", i.e., completely reflects the light flux. The working substance (active medium), in which the inverse population is created, is placed between the mirrors. Stimulated radiation passes through the active medium, is amplified, reflected from the mirror, again passes through the medium, and is further amplified. Through a translucent mirror, part of the radiation is emitted into the external medium, and part is reflected back into the medium and amplified again. Under certain conditions, the photon flux inside the working substance will begin to grow like an avalanche, and the generation of monochromatic coherent light will begin.

The principle of operation of an optical resonator, the predominant number of particles of the working substance, represented by light circles, are in the ground state, i.e., at the lower energy level. Only a small number of particles, represented by dark circles, are in an electronically excited state. When the working substance is exposed to a pumping source, the main number of particles goes into an excited state (the number of dark circles has increased), and an inverse population is created. Further (Fig. 2c), spontaneous emission of some particles in an electronically excited state occurs. Radiation directed at an angle to the resonator axis will leave the working substance and the resonator. Radiation directed along the resonator axis will approach the mirror surface.

At a semitransparent mirror, part of the radiation will pass through it into the environment, and part will be reflected and again directed to the working substance, involving particles in an excited state in the process of stimulated emission.

At the “deaf” mirror, the entire ray flux will be reflected and again pass through the working substance, inducing the radiation of all remaining excited particles, which reflects the situation when all excited particles gave up their stored energy, and at the output of the resonator, on the side of the semitransparent mirror, a powerful flux of induced radiation was formed.

The main structural elements of lasers include a working substance with certain energy levels of their constituent atoms and molecules, a pump source that creates an inverse population in the working substance, and an optical resonator. There are a large number of different lasers, but they all have the same and, moreover, a simple circuit diagram of the device, which is shown in Fig. 3.

The exception is semiconductor lasers due to their specificity, since they have everything special: the physics of the processes, the pumping methods, and the design. Semiconductors are crystalline formations. In a separate atom, the energy of an electron takes strictly defined discrete values, and therefore the energy states of an electron in an atom are described in terms of levels. In a semiconductor crystal, energy levels form energy bands. In a pure semiconductor that does not contain any impurities, there are two bands: the so-called valence band and the conduction band located above it (on the energy scale).

Between them there is a gap of forbidden energy values, which is called the band gap. At a semiconductor temperature equal to absolute zero, the valence band must be completely filled with electrons, and the conduction band must be empty. In real conditions, the temperature is always above absolute zero. But an increase in temperature leads to thermal excitation of electrons, some of them jump from the valence band to the conduction band.

As a result of this process, a certain (relatively small) number of electrons appears in the conduction band, and the corresponding number of electrons will be lacking in the valence band until it is completely filled. An electron vacancy in the valence band is represented by a positively charged particle, which is called a hole. The quantum transition of an electron through the band gap from bottom to top is considered as the process of generating an electron-hole pair, with electrons concentrated at the lower edge of the conduction band, and holes - at the upper edge of the valence band. Transitions through the forbidden zone are possible not only from the bottom up, but also from the top down. This process is called electron-hole recombination.

When a pure semiconductor is irradiated with light whose photon energy somewhat exceeds the band gap, three types of interaction of light with a substance can occur in a semiconductor crystal: absorption, spontaneous emission, and stimulated emission of light. The first type of interaction is possible when a photon is absorbed by an electron located near the upper edge of the valence band. In this case, the energy power of the electron will become sufficient to overcome the band gap, and it will make a quantum transition to the conduction band. Spontaneous emission of light is possible with the spontaneous return of an electron from the conduction band to the valence band with the emission of an energy quantum - a photon. External radiation can initiate a transition to the valence band of an electron located near the lower edge of the conduction band. The result of this third type of interaction of light with the substance of a semiconductor will be the birth of a secondary photon, identical in its parameters and direction of motion to the photon that initiated the transition.

To generate laser radiation, it is necessary to create an inverse population of “working levels” in the semiconductor - to create a sufficiently high concentration of electrons at the lower edge of the conduction band and, accordingly, a high concentration of holes at the edge of the valence band. For these purposes, pure semiconductor lasers usually use pumping with an electron beam.

The mirrors of the resonator are the polished edges of the semiconductor crystal. The disadvantage of such lasers is that many semiconductor materials generate laser radiation only at very low temperatures, and the bombardment of semiconductor crystals with an electron beam causes it to be strongly heated. This requires additional cooling devices, which complicates the design of the apparatus and increases its dimensions.

The properties of doped semiconductors differ significantly from those of undoped, pure semiconductors. This is due to the fact that the atoms of some impurities easily donate one of their electrons to the conduction band. These impurities are called donor impurities, and a semiconductor with such impurities is called an n-semiconductor. Atoms of other impurities, on the contrary, capture one electron from the valence band, and such impurities are acceptor, and a semiconductor with such impurities is a p-semiconductor. The energy level of impurity atoms is located inside the band gap: for n-semiconductors, not far from the lower edge of the conduction band; for f-semiconductors, near the upper edge of the valence band.

If an electric voltage is created in this region so that there is a positive pole on the side of the p-semiconductor and a negative pole on the side of the n-semiconductor, then under the action of the electric field, electrons from the n-semiconductor and holes from the p-semiconductor will move (inject) into area pn - transition.

During the recombination of electrons and holes, photons will be emitted, and in the presence of an optical resonator, generation of laser radiation is possible.

The mirrors of the optical resonator are the polished faces of the semiconductor crystal, oriented perpendicular to the pn junction plane. Such lasers are characterized by miniaturization, since the dimensions of the semiconductor active element can be about 1 mm.

Depending on the feature under consideration, all lasers are subdivided as follows).

First sign. It is customary to distinguish between laser amplifiers and generators. In amplifiers, weak laser radiation is supplied at the input, and at the output it is correspondingly amplified. There is no external radiation in the generators; it arises in the working substance due to its excitation with the help of various pump sources. All medical laser devices are generators.

The second sign is the physical state of the working substance. In accordance with this, lasers are divided into solid-state (ruby, sapphire, etc.), gas (helium-neon, helium-cadmium, argon, carbon dioxide, etc.), liquid (liquid dielectric with impurity working atoms of rare earth metals) and semiconductor (arsenide -gallium, arsenide-phosphide-gallium, selenide-lead, etc.).

The method of excitation of the working substance is the third distinguishing feature of lasers. Depending on the excitation source, there are lasers with optical pumping, with pumping due to a gas discharge, electronic excitation, charge carrier injection, with thermal, chemical pumping, and some others.

The emission spectrum of the laser is the next sign of classification. If the radiation is concentrated in a narrow wavelength range, then it is customary to consider the laser to be monochromatic and a specific wavelength is indicated in its technical data; if in a wide range, then the laser should be considered broadband and the wavelength range should be indicated.

According to the nature of the emitted energy, pulsed lasers and continuous-wave lasers are distinguished. The concepts of a pulsed laser and a laser with frequency modulation of continuous radiation should not be confused, since in the second case we get, in fact, discontinuous radiation of different frequencies. Pulsed lasers have a high power in a single pulse, reaching 10 W, while their average pulse power, determined by the corresponding formulas, is relatively low. For cw lasers with frequency modulation, the power in the so-called pulse is lower than the power of continuous radiation.

According to the average output radiation power (the next classification feature), lasers are divided into:

high-energy (created flux density radiation power on the surface of an object or biological object - more than 10 W/cm2);

medium-energy (created flux density radiation power - from 0.4 to 10 W / cm2);

· low-energy (created flux density radiation power - less than 0.4 W/cm2).

soft (generated energy exposure - E or power flux density on the irradiated surface - up to 4 mW/cm2);

average (E - from 4 to 30 mW/cm2);

hard (E - more than 30 mW / cm2).

In accordance with the Sanitary Norms and Rules for the Design and Operation of Lasers No. 5804-91, according to the degree of danger of the generated radiation for the operating personnel, lasers are divided into four classes.

Lasers of the first class include such technical devices, the output collimated (contained in a limited solid angle) radiation of which does not pose a danger when irradiated to the eyes and skin of a person.

Lasers of the second class are devices whose output radiation is dangerous when exposed to the eyes by direct and specularly reflected radiation.

Lasers of the third class are devices whose output radiation is dangerous when the eyes are exposed to direct and specularly reflected, as well as diffusely reflected radiation at a distance of 10 cm from a diffusely reflective surface, and (or) when the skin is exposed to direct and specularly reflected radiation.

Lasers of the fourth class are devices whose output radiation is dangerous when the skin is exposed to diffusely reflected radiation at a distance of 10 cm from a diffusely reflective surface.

Who in childhood did not dream of laser? Some men still dream. Ordinary laser pointers with low power are no longer relevant, as their power leaves much to be desired. There are 2 ways left: buy an expensive laser or make it at home from improvised means.

From an old or broken DVD drive
From a computer mouse and a flashlight
From a kit of parts purchased from an electronics store

How to make a laser at home from the oldDVDdrive

Find a non-working or unwanted DVD drive capable of recording at speeds greater than 16x that put out more than 160mW of power. Why can't you take a CD burner, you ask. The fact is that its diode emits infrared light, which is not visible to the human eye.
Remove the laser head from the drive. To access the “innards”, unscrew the screws located on the bottom of the drive and remove the laser head, which is also held in place with screws. It can be in a shell or under a transparent window, or maybe even outside. The most difficult thing is to extract the diode itself from it. Attention: the diode is very sensitive to static electricity.
Get a lens, without which the use of the diode will be impossible. You can use an ordinary magnifying glass, but then you have to twist and adjust it every time. Or you can purchase another diode complete with a lens, and then replace it with the diode removed from the drive.
Then you have to buy or assemble a circuit to power the diode and assemble the structure together. In the diode of a DVD drive, the center pin acts as a negative terminal.
Connect a suitable power supply and focus the lens. It remains only to find a suitable container for the laser. You can use a metal flashlight for these purposes, suitable in size.
We recommend watching this video, where everything is shown in great detail:

How to make a laser from a computer mouse

The power of a laser made from a computer mouse will be much less than the power of a laser made in the previous way. The manufacturing process is not much different.

First of all, find an old or unwanted mouse with a visible laser of any color. Mice with an invisible glow will not work for obvious reasons.
Next, carefully disassemble it. Inside you will notice a laser that will have to be soldered with a soldering iron.
Now repeat steps 3-5 from the above instructions. The difference between such lasers, we repeat, is only in power.

Hello ladies and gentlemen. Today I am opening a series of articles on powerful lasers, because habrapoisk says that people are looking for similar articles. I want to tell you how you can make a fairly powerful laser at home, and also teach you how to use this power not just for the sake of “shine on the clouds”.

A warning!

The article describes the manufacture of a high-power laser ( 300mW ~ power 500 Chinese pointers), which can harm your health and the health of others! Be extremely careful! Use safety goggles and do not point the laser beam at people or animals!

Let's find out.

On Habré, articles about portable lasers Dragon Lasers, such as Hulk, slipped just a couple of times. In this article I will tell you how you can make a laser that is not inferior in power to most models sold in this store.

Cooking.

First you need to prepare all the components:
- non-working (or working) DVD-RW drive with a recording speed of 16x or higher;
- capacitors 100 pF and 100 mF;
- resistor 2-5 Ohm;
- three AAA batteries;
- soldering iron and wires;
- collimator (or Chinese pointer);
- steel LED lamp.

This is a necessary minimum for the manufacture of a simple driver model. The driver is, in fact, a board that will output our laser diode to the required power. It is not worth connecting the power source directly to the laser diode - it will fail. The laser diode must be powered by current, not voltage.

A collimator is, in fact, a module with a lens that reduces all radiation into a narrow beam. Ready-made collimators can be bought at radio stores. These already immediately have a convenient place to install a laser diode, and the cost is 200-500 rubles.

You can also use a collimator from a Chinese pointer, however, the laser diode will be difficult to fix, and the body of the collimator itself will most likely be made of metallized plastic. So our diode will be poorly cooled. But this is also possible. This option can be seen at the end of the article.

We do.

First you need to get the laser diode itself. This is a very fragile and small part of our DVD-RW drive - be careful. A powerful red laser diode is located in the carriage of our drive. You can distinguish it from a weak one by a larger radiator than a conventional IR diode.

It is recommended to use an anti-static wrist strap as the laser diode is very sensitive to static electricity. If there is no bracelet, then you can wrap the diode leads with a thin wire while it waits for installation in the case.

According to this scheme, you need to solder the driver.

Do not reverse the polarity! The laser diode will also fail instantly if the polarity of the input power is reversed.

The diagram shows a 200 mF capacitor, however, 50-100 mF is enough for portability.

We try.

Before installing the laser diode and assembling everything into the case, check the driver's performance. Connect another laser diode (non-working or the second one from the drive) and measure the current with a multimeter. Depending on the speed characteristics, the current strength must be selected correctly. For 16x models, 300-350mA is quite suitable. For the fastest 22x, even 500mA can be applied, but with a completely different driver, the manufacture of which I plan to describe in another article.

Looks terrible, but it works!

Aesthetics.

You can brag about a laser assembled by weight only in front of the same crazy techno-maniacs, but for beauty and convenience it is better to assemble it in a convenient case. Here it is better to choose the way you like it. I mounted the whole circuit in a regular LED flashlight. Its dimensions do not exceed 10x4cm. However, I do not advise you to carry it with you: you never know what claims can be made by the relevant authorities. And it is better to store in a special case so that the sensitive lens does not get dusty.

This is an option with minimal cost - a collimator from a Chinese pointer is used:

Using a factory-produced module will produce the following results:

The laser beam is visible in the evening:

And, of course, in the dark:

Maybe.

Yes, I want to tell and show in the following articles how such lasers can be used. How to make much more powerful specimens that can cut metal and wood, and not just set fire to matches and melt plastic. How to make holograms and scan objects to get 3D Studio Max models. How to make powerful green or blue lasers. The scope of lasers is quite wide, and one article is not enough.

Need to remember.

Don't forget about safety! Lasers are not toys! Take care of your eyes!