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 emission. 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
p-n 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. Crystals commonly used are 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 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 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, 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 resonators, which in the elementary version are two coaxial (parallel and along the same 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 again amplified. 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 when an electron spontaneously returns 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 it is not far from the lower edge of the conduction band, for f-semiconductors it is 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 rn - 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 (created 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.
First-class lasers 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.
Class 4 lasers 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.
A laser cutter is a unique gadget that is useful to have in the garage of every modern man. Making a laser for cutting metal with your own hands is not difficult, the main thing is to follow simple rules. The power of such a device will be small, but there are ways to increase it with improvised devices. The functionality of a production machine, which, without embellishment, can do anything, cannot be achieved by homemade work. But for household chores, this unit will come in handy. Let's see how to build it.
Everything is ingeniously simple, so to create such equipment that can cut the most beautiful patterns in strong steels, you can make it from ordinary materials at hand. For manufacturing, you will definitely need an old laser pointer. In addition, stock up on:
- Flashlight powered by rechargeable batteries.
- An old DVD-ROM from which we need to extract the laser drive matrix.
- Soldering iron and screwdriver set.
The first step is to disassemble the drive of the old computer drive. From there we should remove the device. Be careful not to damage the device itself. The disk drive must be a writer, not just a reader, the point is in the structure of the device matrix. Now we will not go into details, but just use modern non-working models.
After that, you will definitely need to remove the red diode that burns the disc while writing information to it. We just took a soldering iron and unsoldered the fasteners of this diode. Just don't throw it away. This is a sensitive element that, if damaged, can quickly deteriorate.
When assembling the laser cutter itself, consider the following:
- Where is the best place to install a red diode
- How will the elements of the entire system be powered?
- How will the electric current flows in the part.
Remember! The diode that will perform the burn requires much more electricity than the elements of the pointer.
The solution to this dilemma is simple. The diode from the pointer is replaced by a red light from the drive. You should disassemble the pointer with the same care as the drive, damage to the connectors and holders will ruin your future with your own hands. When you have done this, you can start making a homemade case.
To do this, you will need a flashlight and rechargeable batteries that will power the laser cutter. Thanks to the flashlight, you will get a convenient and compact item that does not take up much space in your home. The key to the equipment of such a case is to choose the correct polarity. The protective glass is removed from the former flashlight so that it is not an obstacle to the directional beam.
The next step is to power the diode itself. To do this, you need to connect it to the battery charger, observing the polarity. Finally, check:
- Reliability of device fixation in clamps and clamps;
- Device polarity;
- beam direction.
Screw inaccuracies, and when everything is ready, you can congratulate yourself on the successful completed work. The cutter is ready to use. The only thing to remember is that its power is much less than the power of its production counterpart, so too thick metal is beyond its power.
Carefully! The power of the device is enough to harm your health, so be careful while operating and try not to put your fingers under the beam.
Strengthening the homemade installation
To enhance the power and density of the beam, which is the main cutting element, you should prepare:
- 2 "conders" for 100 pF and mF;
- Resistance at 2-5 ohms;
- 3 rechargeable batteries;
- collimator.
The installation that you have already assembled can be strengthened in order to get enough power in everyday life for any work with metal. When working on amplification, remember that plugging your cutter directly into an outlet will be suicidal for it, so care must be taken to ensure that the current first hits the capacitors, after which it is given to the batteries.
By adding resistors you can increase the power of your installation. To further increase the efficiency of your device, use a collimator that is mounted to collect the beam. Such a model is sold in any store for an electrician, and the cost ranges from 200 to 600 rubles, so it is not difficult to buy it.
Further, the assembly scheme is carried out in the same way as discussed above, only aluminum wire should be wound around the diode to remove static. After that, you have to measure the current strength, for which a multimeter is taken. Both ends of the device are connected to the remaining diode and measured. Depending on your needs, you can adjust the readings from 300mA to 500mA.
After the current calibration is done, you can proceed to the aesthetic decoration of your torch. For the case, an old steel flashlight with LEDs will do just fine. It is compact and fits in your pocket. To prevent the lens from getting dirty, be sure to get a case.
Store the finished cutter in a box or case. Dust or moisture must not enter there, otherwise the device will be disabled.
What is the difference between ready models
Cost is the main reason why many craftsmen resort to making their own laser cutter. And the working principle is as follows:
- Due to the creation of a directional laser beam, the metal is affected
- Powerful radiation causes the material to evaporate and exit under the force of the flow.
- As a result, thanks to the small diameter of the laser beam, a high-quality cut of the workpiece is obtained.
The depth of cut will depend on the power of the components. If the factory models are equipped with high quality materials that provide a sufficient depth indicator. Then home-made models are able to cope with a crash of 1-3 cm.
Thanks to such laser systems, you can make unique patterns in the fence of a private house, accessories for decorating gates or fences. There are only 3 types of cutters:
- Solid state. The principle of operation is tied to the use of special types of glass or crystals of LED equipment. These are inexpensive production units that are used in production.
- Fiber. Thanks to the use of optical fiber, a powerful flow and sufficient cutting depth can be obtained. They are analogues of solid models, but due to their capabilities and performance characteristics, they are better. But also more expensive.
- Gas. From the name it is clear that gas is used for operation. It can be nitrogen, helium, carbon dioxide. The efficiency of such devices is 20% higher than that of all previous ones. They are used for cutting, welding polymers, rubber, glass and even metal with a very high level of thermal conductivity.
In everyday life, you can only get a solid-state laser cutter at no extra cost, but its power, with proper amplification, which was discussed above, is enough to perform household work. Now you have the knowledge regarding the manufacture of such a device, and then just act and try.
Do you have experience in developing a laser cutter for metal with your own hands? Share with readers by leaving a comment below this article!
Many people are aware of the possibilities of laser technologies and their benefits. They are used not only in industry, but also in cosmetology, medicine, everyday life, art and other areas of human life. However, not everyone knows how to make a laser at home. But it can be built from improvised materials. To do this, you will need a non-working DVD drive, a lighter or a flashlight.
Before at home, you need to collect all the necessary elements. First of all, you need to disassemble the DVD drive. To do this, all the screws that hold the top and bottom covers of the device are unscrewed. Next, the main cable is disconnected and the board is unscrewed. Protection of diodes and optics must be cracked. The next step is to remove the diode, for which pliers are usually used. In order for static electricity not to damage the diode, its legs must be tied with wire. Remove the diode carefully so as not to break the legs.
Next, before making a laser at home, you need to make a driver for the laser, which is represented by a small circuit that regulates the power of the diode. The fact is that if the power is set incorrectly, then the diode can quickly fail. As a power source, you can use finger batteries or a battery from a mobile phone.
Before you make a laser at home, you need to take into account the fact that the burning effect is provided by optics. If not, then the laser will just shine. As optics, you can use a special lens from the same drive from which the diode was taken. To correctly set the focus, you must use a laser pointer.
In order to build a regular pocket laser, you can use a regular lighter. However, before you make a laser from a lighter, you need to know the construction technology. It is best to purchase a quality incendiary element. It needs to be disassembled, but the parts should not be thrown away, as they will still be useful in the design. If there is gas left in the lighter, it must be released. Then the insides must be machined with a drill with special nozzles. Inside the body of the lighter there is a diode from the drive, several resistors, a switch and a battery. All elements of the lighter must be installed in their places, after which the button that used to light the flame will turn on the laser.
However, for the construction of the device, you can use not only a lighter, but also a flashlight. Before you can make a laser from a flashlight, you need to take the laser block from the CD drive. In principle, the structure of a homemade laser in a flashlight does not differ from the laser device in a lighter. It is only necessary to take into account the power supply, which almost never exceeds 3 V, and it is also desirable to build an additional voltage regulator. It will increase the life It is very important to consider the polarity of the diode and the stabilizer.
All the assembled filling must be placed in the body of the disassembled flashlight. Previously, not only the inner part, but also the glass is removed from the flashlight. After installing the laser unit, the glass is installed in place.
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”.
Warning!
The article describes the manufacture of a powerful laser (300mW ~ power of 500 Chinese pointers), which can harm your health and the health of others! Be extremely careful! Use special protective goggles and do not direct the laser beam at people or animals!
On Habré, articles about portable 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.
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. A driver is, in fact, a board that will output our laser diode to the required power. It is not worth connecting a 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.
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.
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 costs - 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.
Attention! Don't forget about safety! Lasers are not toys! Take care of your eyes!
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 disk 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.