How to make an igniting laser at home. How to make a laser that burns through

In every house there is an old, worn-out technique. Someone throws it into a landfill, and some craftsmen try to use it for some self-made inventions. So an old laser pointer can be used worthily - 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 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 proprietary cutter, but in the absence of a regular cutter, a regular one 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 have to be patient and pay maximum attention. Since it contains a large number of wires, the structure is the same. When choosing a drive, it is important to take into account the availability of a writing version, since it is in this model that you can make records with a laser. Recording is performed by evaporation of a thinly applied layer of metal from the disc itself. In the case when the laser works for reading, it is used half-heartedly, illuminating the disc.

When dismantling the upper 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, which are important to carefully remove. For further work, a red diode is needed, with the help of 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 the irreplaceable part for the manufacture of a laser cutter must not be shaken or 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, it is necessary to carefully weigh everything and figure out where to place it and how to connect the power supply to it, since the writing laser diode requires 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 of the pointers, the native diode must be removed and replaced with a similar one from the CD / DVD-RW drive. The pointer is disassembled in accordance with the 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 times when difficulties may arise when removing the old diode, in this situation you can use a knife and shake the pointer a little.

The next step is to make 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 a flashlight body. 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 a 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, since it will be difficult to conduct the direct path of the laser beam.

The last step is preparation for use. Before connecting, check that the laser is firmly attached, that the polarity of the wires is connected correctly, and that the laser is level.

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

Additional points

A more powerful laser can be made. To make it you will need:

dVD-RW drive, can be inoperative;
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 simple kit that is completed for assembling 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 diode for the laser must be supplied with current, but not voltage.

A collimator is a body equipped with a lens, due to which all 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 the body from the pointer, but it will be difficult to attach the 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.

Anti-static bracelets must be used during manufacture.

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, the driver is assembled.

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

Of course, such a laser can be assembled by any non-professional technician, but still, for beauty and convenience, such a device is most reasonable to build 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 body of an LED flashlight, since its dimensions are compact, only 10x4 cm. Still, you do not need to carry such a device in your pocket, since the relevant authorities can make claims. It is best to store such a device in a special case to avoid dusting the lens.

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

Safety engineering

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

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

Do not point the laser beam at flammable or explosive objects.
Do not shine into reflective surfaces (glass, mirrors).
Even a laser beam launched from a distance of up to 100 m poses a danger to the retina of humans and animals.

Working with the laser module

The main thing we need is a recorder. Note, the higher its 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 only disassemble the device that you no longer need.

Now let's start:

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

Assembling the device diagram

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

For our device, a wall-mounted installation is quite suitable. Now let's move on to providing power to a self-made laser.

Power supply to the device

We will need a minimum of 3.7 V. This can be provided by old batteries from mobile phones, finger batteries. You just need to connect them in parallel with each other. To check the operation of a 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. Looks like a powerful infrared flashlight in the dark.

You see that while the glow is far from the laser one: 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 device to the power supply, directing its light onto some surface already through this lens. Happened? Then we proceed to the final stage of work - placing all the elements in a rigid case.

Manufacturing of the case

Many, advising on 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 your fingertips.

Alternatively, 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, you will be guided by the photo below.

Be sure to insulate all contacts. The next step is fixing the lens in the body. It is easiest to attach it to plasticine - this way you can adjust the most successful position. In some cases, the best effect is obtained if you flip the lens upside down towards the laser diode.

Turn on the laser and adjust the clarity of the beam. Once you have achieved satisfactory results, lock the lens into the housing. Then close it completely, for example, by wrapping it tightly with electrical tape.

How to make a laser: an alternative way

We will offer you another, somewhat excellent way of making a homemade powerful laser. You will need the following:

DVD-RW drive with a write speed of 16x or more.
Three AA batteries.
Capacitors 100mF and 100pF.
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 from the drive, which is located in the carriage of the device, using the method already described. Remember to protect it from static electricity by wrapping fine wire around the outputs or wearing an antistatic wrist strap.
According to the above diagram, solder the driver - a board that will bring our homemade product to the required power. Pay close attention to correct polarity so as not to damage the sensitive laser diode.
At this stage, we will test the functionality of the newly assembled driver. If the laser module is from the 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 the suitability of the driver, you need to place it in the case. It can be either a base from a Chinese laser pointer with an already mounted lens, or a more suitable body for 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 the asphalt, stone, brick. Aim the already well-focused laser beam at it. You will see that after a while the leaf will start to smoke, and then will completely ignite.
Now let's move on to the plastic - it will also start to smoke from the laser beam. We do not recommend carrying out such experiments for a long time: the combustion products of this material are very toxic.
The most interesting experience is with plywood, flat board. With a focused laser, you can burn out a certain inscription, drawing on it.

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

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

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

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

By the principle of its operation, a laser is a quantum photon generator. The essence of the phenomenon underlying it lies in the fact 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. Household lasers (laser disc drives, laser printers) use semiconductor method stimulation of radiation by electric current.

The principle of operation consists in the passage of an air stream 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. Repair tips can be read.

In addition, a necessary component of any full-fledged laser is optical resonator, the function of which is to amplify the light beam by multiple reflection. 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. To do this, you must have special knowledge, carry out complex calculations, have a good material and technical base.

For example, lasers that can cut metal are extremely hot and require extreme cooling measures, including the use of liquid nitrogen. In addition, devices operating on the basis of 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). Includes a 300 mW red laser diode. 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 produces a current of 1A, stabilizes the voltage in the range of 0.9-3.9 V. These figures are ideal for our laser diode, which requires a constant voltage of 3 V.
Collimator for obtaining an even beam of light. Numerous laser modules from various manufacturers are now on sale, 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. You will also need a screwdriver and tweezers.

How to make a laser from a floppy drive?

The assembly procedure for 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 such a homemade "light amplifier" can do:

Light a match from a distance.
Melting plastic bags and tissue paper.
Emit a beam over a distance of 100 meters.

This laser is hazardous: it will not burn skin or clothing, but it can damage your eyes.
Therefore, you need to use such a device carefully: do not shine it into 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.

DIY laser on video

Turn your MiniMag Laser Pointer into a Cutting Laser with a DVD Writer Emitter! This 245mW laser is very powerful and fits perfectly with the MiniMag pointer! Watch the attached video. PLEASE NOTE: you can do this with your own hands NOT WITH ALL CDRW-DVD cutter diodes!

Warning: CAUTION! As you know, lasers can be dangerous. Never point the pointer over a living creature! It is not a toy and should not be handled like a normal laser pointer. In other words, don’t use it in presentations or when playing with animals, don’t let children play with it. This device must be in the hands of a sane person who understands and is responsible for the potential hazards that the pointer poses.

step 1 - What do 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 home improvement store.

3. AixiZ case with AixiZ for $ 4.5

4. Small screwdrivers (watch), office knife, metal scissors, 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. Below it you will find the laser carriage drive assembly.

step 4 - Remove the laser diode ...

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

step 5 - We continue to disassemble ...

After removing the carriage from the drive, begin to disassemble the device by loosening 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 a disc (infrared diode) and a red diode itself, with which the burning is carried out. You need a second one. A printed circuit board is attached to the red diode using 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 remove the diode from the case, which will differ depending on the drive. The laser diode is very fragile, so be very careful.

step 6 - Laser diode in a new guise!

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

step 7 - Preparing the AixiZ body ...

Peel off the sticker from the AixiZ case and twist the case onto the top and bottom. Inside the top is a laser diode (5 mW), which we will replace. I used the X-Acto knife and after two light blows, the native diode came out. Actually, 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 body ...

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

step 9 - Install it in MiniMag

After the two wires have been soldered to the positive and negative terminals of the diode, you can install the device in the MiniMag. After disassembling the MiniMag (remove the cover, reflector, lens and emitter), you will need to enlarge the MiniMag reflector using a round file or 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 the top of the MiniMag where the emitter was previously. Assemble the upper part of the MiniMag housing, secure the reflector. The plastic MiniMag lens is useless.

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 focus of the beam.

step 11 - Measure seven times

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

]Book

Name
Author: collective
Format: Mixed
The size: 10.31 Mb
Quality: Excellent
Tongue: Russian
The year of publishing: 2008

Like in a science fiction movie - you pull the trigger and the ball explodes! Learn to make such a laser!
You can make such a laser yourself, at home from a DVD drive - not necessarily a worker. Nothing complicated!
Sets fire to matches, pops balloons, cuts bags and duct tape and much more
They can also burst a ball or light bulb in the house opposite
In the archive - a video with a laser in action and detailed Russian instructions with pictures for its manufacture!

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 at laser levels and.

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

This allows you to burn a layer of the disc, putting digital tracks 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 a classical p-n junction. This transition works as in conventional LEDs.

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

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 mechanically cleaved, 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 "heterojunction", with different junction materials.

The laser diode itself is an affordable radio component. It can be purchased from radio stores or removed from an old DVD-R (DVD-RW) drive.

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

More powerful installations with a burning beam can blind or burn 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.

DIY laser from 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 price.

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

After removing the case and disconnecting 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 using a wire (shunt). When dismantled, static electricity can build up and the diode can be damaged.
Removing the aluminum radiator. It is quite fragile, has a fastening, structurally "sharpened" for a specific DVD drive, and is not needed in further operation. Just bite the radiator with pliers (without damaging the diode)
We solder the diode, release the legs from the shunt.

The element looks like this:

The next important element is the laser power supply circuit. You cannot use a power supply from a DVD drive. It is integrated into the general control scheme; it is technically impossible to extract it from there. Therefore, we make the supply circuit ourselves.

It's tempting to just plug in a 5 volt 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 according to the supply current of the laser diode. In this circuit, the current must 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 module for a laser 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 included. The power supply circuit (driver) fits easily into the module case.

If you decide to make the case yourself, from a metal tube, you can use a standard lens from the same DVD drive. You just need to come up with a mounting method, and the possibility of adjusting the focus.

Important! It is necessary to focus the beam with any design. It can be parallel (if range is needed) or cone-shaped (if necessary, to obtain a concentrated thermal spot).

A lens complete with an adjusting device is called a collimator.

To correctly connect the laser from the DVD drive, you need a contact diagram. You can trace the negative and positive wires by the 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 is electrically connected to the diode body. Finding it will not be difficult. With respect to the minus located at the bottom, the positive contact will be on the right.

If you have a three-legged laser diode (and there are most of them), there will be either an unused contact or a photodiode connection on the left. 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. Gently 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 out 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 the standard diode from the DVD drive is not enough. You will need either a ready-made 500-800 mW diode, or you will have to spend a lot of time looking for suitable DVD drives. Some LG and SONY models are equipped with 250-300mW laser diodes.

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

A step-by-step video instruction on 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 improvised means, but few people know how to make a laser on their own. Before you start working on it, be sure to read the safety precautions.

Laser safety rules

Improper use of a beam, especially a high power beam, can damage property and severely harm your health or the health of bystanders. Therefore, before you test your own made copy, remember the following rules:

Make sure there are no animals or children in the test room.
Never aim the beam at animals or people.
Use protective goggles such as welding goggles.
Remember that even a reflected beam can damage your eyesight. Never shine a laser in your eyes.
Do not use the laser to ignite objects in an enclosed space.

The simplest laser from a computer mouse

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

The mouse must be disassembled first. It is important not to break them out, but carefully unwind and remove them in order. First the upper casing, then the lower one. 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 bring the wiring to the battery contacts. Any type of battery can be used: both finger 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 complex method of making it, using a DVD-RW drive.

To work you will need:

DVD-RW drive (write speed must be at least 16x);
aAA battery, 3 pcs .;
resistor (from two to five ohms);
collimator (can be replaced with a part from a cheap Chinese laser pointer);
capacitors 100 pF and 100 mF;
lED flashlight made of steel;
wires and a soldering iron.

Work progress:

The first thing we need is a laser diode. It is located in the carriage of the DVD-RW drive. It has a larger heat sink than conventional infrared diode. But be careful, this part is fragile. While the diode is not installed, it is best to wrap its lead with wire as it is too sensitive to static voltage. Pay particular 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 efficiency of the structure has been verified, it remains only to come up with a convenient housing for the laser. For these purposes, a steel case from a conventional lantern is quite suitable. Do not forget about the collimator, because it is he who converts the radiation into a thin beam.

Now that you know how to make a laser at home, do not forget about safety precautions, keep it in a special case and do not carry it with you, as law enforcement agencies may make claims to you 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 a powerful green or blue laser yourself at home from improvised materials with your own hands. We will also consider the drawings, diagrams and the device of homemade laser pointers with an incendiary 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 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 action of another photon without absorbing it, if the energy of the latter is equal to the difference between the energies of the levels of the atom before and after radiation. In this case, the emitted photon is coherent to the photon that caused the radiation, that is, it is its exact copy. Thus, the light is amplified. This 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 the induced emission of an excited atom is exactly equal to the probability that this photon will be absorbed by an atom in an unexcited state. Therefore, to amplify light, it is necessary that there are more excited atoms in the medium than unexcited ones. In a state of equilibrium, this condition is not fulfilled; 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; an inverse population is created inside it using various pump sources. There are different pumping methods depending on the sources:
optical - powerful flash lamp;
gas discharge in the working substance (active medium);
injection (transfer) of current carriers in a semiconductor in the
pn transitions;
electronic excitation (irradiation in a vacuum of a pure semiconductor with an electron flow);
thermal (heating the gas followed by its sharp cooling;
chemical (use of 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, the existence of a positive feedback is necessary, due to which the emitted photons cause subsequent acts of induced emission. For this, the active medium of the laser is placed in an optical cavity. In the simplest case, it consists of two mirrors, one of which is semitransparent - through it the laser beam partially leaves the resonator.

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

The radiation generated by the laser is monochromatic, the probability of emission of a photon of a certain wavelength is higher than that of a closely located one, associated with 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 the mirrors, only those photons are retained in the laser beam that propagate in a direction parallel to the optical axis of the resonator at a short distance from it, the rest of the photons quickly leave the cavity volume. Thus, the laser beam has a very small divergence angle. Finally, the laser beam has a strictly defined polarization. For this, various polarizers are introduced into the resonator, for example, they can be flat glass plates installed at a Brewster angle to the direction of propagation of the laser beam.

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

So, let us briefly formulate the conditions necessary for creating a source of coherent light:

you need a working substance with an inverse population. Only then can the amplification of light be obtained due to forced transitions;
the working substance should be placed between the mirrors that provide feedback;
the amplification 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 medium, for example, in dye lasers. The composition contains 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 such as in helium-neon lasers. These lasers are most often "pumped" with energy by means of electrical discharges.
Solids (crystals and glasses). The solid material of such working bodies is activated (doped) by adding a small amount of chromium, neodymium, erbium or titanium ions. The following crystals are commonly used: yttrium aluminum garnet, lithium yttrium fluoride, sapphire (aluminum oxide) and silicate glass. Solid state lasers are usually "pumped" by 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 an electric current, which allows them to be used in home appliances such as CD players.

To turn an amplifier into an oscillator, it is necessary to provide feedback. In lasers, it is achieved by placing an active substance between reflective surfaces (mirrors), forming a so-called "open resonator" due to the fact that part of the energy emitted by the active substance is reflected from the mirrors and returns to the active substance

The Laser uses various types of optical resonators - with flat mirrors, spherical, combinations of flat and spherical, etc. In optical resonators that provide feedback in the Laser, only certain specific types of electromagnetic field oscillations can be excited, which are called natural oscillations or resonator modes.

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

The use of an open resonator (and not a closed - closed metal cavity - characteristic of the microwave range) is fundamental, since in the optical range a resonator with dimensions L \u003d? (L is the characteristic size of the resonator,? Is the wavelength) simply cannot be manufactured, and for L \u003e\u003e? a closed resonator loses its resonant properties, since 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 axis of the resonator quickly leave its limits, and allows maintaining the resonant properties of the resonator at L \u003e\u003e?. However, the cavity in the laser not only provides feedback due to the return of the radiation reflected from the mirrors to the active substance, but also determines the spectrum of the laser radiation, its energy characteristics, and the directivity of the radiation.
In the simplest plane-wave approximation, the resonance condition in a resonator with flat mirrors is that an integer number of half-waves fits over the resonator length: L \u003d q (λ / 2) (q is an integer), which leads to an expression for the frequency of the vibration type with the index q:? q \u003d q (C / 2L). As a result, the radiation spectrum of a laser, 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) at a given length L depends on the properties of the active medium, i.e., on the spectrum of spontaneous emission at the used quantum transition 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 loss in the cavity 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 working medium line) and the set of natural frequencies of the open resonator. For high-Q open resonators used in lasers, the resonator passband Δp, which determines the width of the resonance curves of individual modes, and even the distance between adjacent modes ΔΔh, turn out to be less than the gain line width ΔΔh, and even in gas lasers, the broadening of the lines is the smallest. Therefore, several types of resonator oscillations fall into the amplification circuit.

Thus, the laser does not necessarily generate at the same frequency; more often, on the contrary, generation occurs simultaneously on several types of oscillations, for which the gain? more losses in the resonator. In order for the laser to operate at one frequency (in single-frequency mode), it is usually necessary to take special measures (for example, to increase losses, as shown in Fig. 3) or to change the distance between the mirrors so that only one fashion. Since in optics, as noted above, ?h\u003e p and the lasing frequency in a laser is determined mainly by the resonator frequency, in order to keep a stable lasing frequency, it is necessary to stabilize the resonator. So, if the gain in the working substance overlaps the losses in the resonator for certain types of oscillations, generation occurs on them. The seed for its occurrence is, as in any generator, noise, which is spontaneous emission in lasers.
In order for the active medium to emit coherent monochromatic light, it is necessary to introduce feedback, that is, to direct part of the light flux emitted by this medium back into the medium for stimulated emission. Positive feedback is carried out using optical resonators, which in an elementary version are two coaxially (parallel and along the same axis) mirrors, one of which is semitransparent, and the other is "dull", that is, fully reflects the light flux. The working substance (active medium), in which the inverse population is created, is placed between the mirrors. The stimulated radiation passes through the active medium, amplifies, reflects from the mirror, passes through the medium again, and becomes even more amplified. Through a semitransparent 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 flux of photons 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 open 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 passes into an excited state (the number of dark circles has increased), and an inverted population is created. Further (Fig. 2c), there is a spontaneous emission of some particles in an electronically excited state. Radiation directed at an angle to the resonator axis will leave the working substance and the resonator. Radiation, which is directed along the axis of the resonator, will approach the mirror surface.

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

At the "dull" mirror, the entire ray flux will be reflected and the working substance will pass through again, inducing the radiation of all the remaining excited particles, where the situation is reflected when all excited particles have given up their stored energy, and at the exit of the resonator, on the side of the semitransparent mirror, a powerful flux of induced radiation is 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 many different lasers, but they all have the same and, moreover, a simple schematic 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 processes, and pumping methods, and design. Semiconductors are crystalline formations. In an individual atom, the energy of an electron takes on 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 a forbidden zone. 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 not be enough 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 forbidden band from bottom to top is considered as a 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 bottom to top, but also from top to bottom. This process is called electron-hole recombination.

When a pure semiconductor is irradiated with light, the photon energy of which is somewhat greater than the band gap, three types of interaction of light with matter can occur in a semiconductor crystal: absorption, spontaneous emission, and forced 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 forbidden zone, 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, the third type of interaction of light with the substance of the semiconductor, will be the creation 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 inverted population of "working levels" in a 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 are usually pumped by an electron flow.

The mirrors of the resonator are the polished faces 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 a stream of electrons 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 semiconductors with impurities differ significantly from the properties of unalloyed, pure semiconductors. This is due to the fact that 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 forbidden band: for n-semiconductors - near the lower edge of the conduction band, for y-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 negative 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 (injected) into area pn - transition.

When electrons and holes recombine, photons will be emitted, and in the presence of an optical cavity, laser radiation can be generated.

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

All lasers are subdivided as follows, depending on the feature under consideration).

The 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 accordingly amplified. There is no external radiation in the generators; it arises in the working substance due to its excitation using various pump sources. All medical laser machines are generators.

The second sign is the physical state of the working substance. In accordance with this, lasers are subdivided 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 exciting the working substance is the third distinguishing feature of lasers. Depending on the excitation source, lasers are distinguished with optical pumping, pumped by a gas discharge, electronic excitation, injection of charge carriers, with thermal, chemical pumping, and some others.

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

Pulsed lasers and continuous-wave lasers are distinguished by the nature of the emitted energy. You should not confuse the concepts of a pulsed laser and a laser with frequency modulation of continuous radiation, since in the second case we receive, in fact, intermittent 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 cw power.

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

· High-energy (generated flux density, radiation power on the surface of an object or biological object - over 10 W / cm2);

· Medium-energy (generated flux density, radiation power - from 0.4 to 10 W / cm2);

· Low-energy (generated flux density, radiation power - less than 0.4 W / cm2).

· Soft (generated energy irradiance - 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 Construction and Operation of Lasers No. 5804-91", lasers are divided into four classes according to the degree of hazard of generated radiation for service personnel.

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

Class II lasers are devices whose output radiation is hazardous when the eyes are exposed to direct and specularly reflected radiation.

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

Class 4 lasers are devices whose output radiation is hazardous when the skin is exposed to diffusely reflected radiation at a distance of 10 cm from the diffusely reflecting surface.

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

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

How to make a laser at home from an old oneDVD drive

Find a dysfunctional or unnecessary DVD drive that has a write speed higher than 16x, and outputs over 160mW. Why can't you take a recording CD, you ask. The fact is that its diode emits infrared light that is invisible to the human eye.
Remove the laser head from the drive. To access the “internals”, unscrew the screws on the bottom of the drive and remove the laser head, which is also held in place by screws. It can be in a shell or under a transparent window, or maybe even outside. The most difficult thing is to remove the diode itself from it. Caution: The diode is very sensitive to static electricity.
Get a lens, without which the use of a diode will be impossible. You can use a regular magnifying glass, but then you have to twist and adjust it every time. Alternatively, you can purchase another diode complete with a lens, and then replace it with a diode removed from the drive.
Then you will have to buy or assemble a circuit to power the diode and assemble the structure together. In a DVD drive diode, the center pin acts as a negative terminal.
Connect a suitable power source and focus the lens. All that remains is to find a suitable container for the laser. For these purposes, you can use a metal flashlight that is 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 with the previous method. The manufacturing procedure is not very different.

The first step is to find an old or unwanted mouse with a visible laser of any color. Mice with an invisible glow will not work for obvious reasons.
Then 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 devoted to powerful lasers, because habrapopisk 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 "shining on the clouds."

Warning!

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

Let's find out.

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

Cooking.

First you need to prepare all the components:
- non-working (or working) DVD-RW drive with a write 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 flashlight.

This is the minimum required to make a simple driver model. A driver is, in fact, a board that will output our laser diode to the required power. You should not connect the power supply directly to the laser diode - it will fail. The laser diode must be powered with current, not voltage.

A collimator is, in fact, a module with a lens that converges all radiation into a narrow beam. Ready-made collimators can be bought at radio stores. In such, there is already a convenient place for installing a laser diode, and the cost is 200-500 rubles.

A collimator from a Chinese pointer can also be used, however, the laser diode will be difficult to fix, and the collimator body itself will most likely be made of metallized plastic. This means that our diode will not cool well. But this is also possible. This option can be found at the end of the article.

We do it.

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 heatsink of a larger size than that of a conventional IR diode.

An ESD wrist strap is recommended as the laser diode is very sensitive to static voltage. If there is no bracelet, then you can wrap a thin wire around the diode leads while it waits for installation in the case.

This scheme requires soldering the driver.

Do not mix up the polarity! The laser diode will also fail instantly if the supply polarity is incorrect.

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

Let's try.

Before installing the laser diode and collecting everything in the case, check the driver's functionality. 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 chosen correctly. For 16x models, 300-350mA is quite suitable. For the fastest 22x, you can even send 500mA, but with a completely different driver, the manufacture of which I plan to describe in another article.

Looks awful, but it works!

Aesthetics.

A laser assembled by weight can only be boasted in front of the same crazy techno-maniacs, but for beauty and convenience it is better to assemble it in a convenient case. It is already better to choose how you like it yourself. I assembled the entire 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 it in a special case so that the sensitive lens does not get dusty.

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

Using a prefabricated module will yield 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 next articles how such lasers can be used. How to make much more powerful specimens that can cut metal and wood, and not only 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 application of lasers is quite wide, and one article cannot be enough here.

You have to remember.

Don't forget about safety precautions! Lasers are not a toy! Take care of your eyes!