Why is the laser pointer green. What is a laser pointer for: applications and safety precautions

Laser pointers are portable devices that contain emitters that generate electromagnetic waves of coherent and monochromatic origin in the visible range in a beam form. Emitters can be laser diodes or full-fledged solid-state lasers.

There are several types of laser pointers, which differ in the types of emitters and are of the following colors:

• Reds;
• Greens;
• Blue;
• Turquoise;
• Blue;
• Violet;
• Yellow;
• Orange.

LU red

These LUs are the cheapest and most common. Operates on a conventional button cell battery based on red laser diodes with a radiation spectrum of 650-660 nm. They are equipped with driver boards for power management. For radiation in the form of a narrow beam, lenses that are convex on both sides, called collimators, are used.

Red LUs are mostly low-power up to 1-100 mW. Their characteristic feature is that the red diodes "burn out" pretty soon, reducing the radiation intensity, which is why most of these pointers, after a couple of months of operation, begin to shine worse, regardless of the battery charge.

LU green (green laser)

During the day, the human eye is more sensitive to green colors than to red (about 6-10 times). This makes the green laser shine more brightly. However, at night, the opposite happens.

Green laser diodes are extremely expensive, so solid-state diode lasers are used to create green lasers. They are not as expensive as green laser diodes, but more valuable than red ones. The green laser wavelength is 532 nm, with an efficiency of approximately 20%. Green LUs are more energy-consuming than red ones, as a result of which it is difficult to select units powered by button-cell batteries.

Lu blue

Began to be produced in 2006, the scheme of action is similar to the green laser. The wavelength is blue - 490 nm, turquoise - 473 nm, and blue - 445 nm. The emitter is a solid-state powerful laser. Blue LUs are very expensive, diodes are not that expensive, but they are not widely used. The blue LU radiation is extremely dangerous for the eyes. The efficiency is approximately 3%.

Lu yellow

The wavelength of yellow LUs is 593.5 nm. There are also their orange counterparts with a wavelength of 635 nm. The efficiency is just over 1%.

Lu purple

LUs with violet laser diodes have a wavelength of 400-410 nm. This is almost the limit in the range that the human eye perceives, so this light appears to be dim.

The light from violet LUs causes fluorescence, and the brightness of the luminous objects becomes more intense than in the laser itself. They went into the series of LUs with the advent of a drive for the optical media Blu-ray, in which a laser diode with a wavelength of the corresponding radiation was used.

LU: application

• LUs are often used by educational institutions, for example, for physical experiments, as well as for presentations;
• The point of light produced by the laser beam attracts the attention of pets. Especially cats and dogs react to them, which often leads people to play with these pets;
• Green LUs are used both in amateur and professional astronomical research. Green LUs are used to determine the directions of stars and constellations;
• LUs are used as laser designators for precise aiming of firearms or pneumatic weapons;
• LUs are used by radio amateurs as a communication element within visible boundaries;
• Red LUs with detached collimators are used to create amateur holograms;
• Laboratory practice uses LUs (especially green ones) to detect in liquids, gases or any transparent substances in small amounts of impurities or suspensions of mechanical origin, which are invisible to the naked eye.

Laser safety

Laser radiation is hazardous in contact with eyes.

Ordinary LUs have a power of 1-5 mW, they are classified as 2-3A hazard classes. They can be dangerous when the beam is directed into the eyes of people for quite long periods or with the help of optical instruments. LUs with a capacity of 50-300 mW are classified as 3B-class. They are dangerous by causing severe damage to the retina of the eyes, even with short-term exposure to a direct laser beam.

Be aware that low power green DPSS pointers use significantly powerful IR lasers, which do not guarantee sufficient IR filtering. Such types of radiation are not visible and as a result are much more dangerous for the eyes of people and animals.

In addition, DRs can be extremely irritating. Especially if the beam hits the eyes of drivers or pilots, which can distract their attention or even lead to blindness. In some countries, such acts are criminalized. For example, in 2019, an American was sentenced to nearly two years in prison for briefly blinding a pilot in a police helicopter with a powerful laser.

In recent years, there have been more and more numerous "laser incidents" in developed countries, caused by requirements to restrict or prohibit drug use. Currently, the legislation of New South Wales provides for a fine for the possession of a license, and for committing a "laser attack" - imprisonment up to 14 years.

The use of LU is prohibited by the rules during football matches. For example, the Algerian Football Federation was fined 50,000 Swiss francs for blinding the goalkeeper of the Russian national team Igor Akinfeev by fans using a laser pointer during the 2014 World Cup.

Most powerful laser pointer

Not so long ago it became known about the emergence of the most powerful pocket laser, the "king" of LU or the "sword of the Jedi." A small, powerful laser can burn through thin plastics, explode baby balls, set fire to paper, and dazzle people. The device of the Chinese manufacturer Wicked Lasers only faintly resembles the popular LU, but has a larger body.

Often, a tiny cylinder laser pointer that emits a red laser beam is used by children for games or for presentations at school. However, Wicked Lasers' new generation signpost for children will not be a toy. And this is no coincidence, because the output power of a Chinese laser pointer is tens and hundreds of times higher than that of conventional inexpensive LUs.

Surprisingly, the Chinese "green supermodel" with a beam power of 0.3 watts reaches a "range" of up to 193 kilometers.

If you have any questions - leave them in the comments below the article. We or our visitors will be happy to answer them.

It is no secret that each of us in childhood wanted to have a device such as a laser machine that could cut metal seals and burn through walls. In the modern world, this dream can easily come true, since now it is possible to build a laser with the ability to cut various materials.

Of course, at home it is impossible to make such a powerful laser installation that will cut through iron or wood. But with a homemade device, you can cut paper, plastic seals, or thin plastic.

The laser device can burn various patterns on plywood sheets or wood. It can be used to illuminate objects located in remote areas. The scope of its application can be both entertaining and useful in construction and installation work, not to mention the realization of creative potential in the field of engraving on wood or plexiglass.

Cutting laser

Tools and accessories that will be required in order to make a laser with your own hands:

Figure 1. Diagram of a laser LED.

• faulty DVD-RW drive with a working laser diode;
• laser pointer or handheld collimator;
• soldering iron and small wires;
• 1 Ohm resistor (2 pcs.);
• capacitors 0.1 uF and 100 uF;
• AAA batteries (3 pcs.);
• small tools such as a screwdriver, knife and file.

These materials will be quite enough for the upcoming work.

So, for a laser device, first of all, you need to choose a DVD-RW drive with a mechanical breakdown, since the optical diodes must be in good working order. If you don't have a worn drive, you will have to purchase it from the people who sell it for parts.

When buying, it should be borne in mind that most of the drives from the manufacturer Samsung are not suitable for making a cutting laser. The fact is that this company produces DVD drives with diodes that are not protected from external influences. The lack of a special housing means that the laser diode is susceptible to heat stress and contamination. It can be damaged by light hand touch.

Figure 2. Laser from DVD-RW drive.

The best option for a laser would be a drive from the manufacturer LG. Each model is equipped with a crystal with different power levels. This figure is determined by the writing speed of dual layer DVD discs. It is extremely important that the drive is a writing drive, since it contains an infrared emitter, which is needed to make a laser. The usual one will not work, since it is intended only for reading information.

DVD-RW with 16X recording speed is equipped with a 180-200 mW red crystal. The 20X drive contains a 250-270 mW diode. The 22X high speed recorders are equipped with laser optics with a power of up to 300 mW.

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Dismantling a DVD-RW drive

This process must be done with great care, as the internal parts are fragile and easily damaged. Having dismantled the case, you will immediately notice the necessary part, it looks like a small piece of glass located inside the movable carriage. Its base and needs to be removed, it is shown in Fig. 1. This element contains an optical lens and two diodes.

At this stage, you should immediately warn that the laser beam is extremely dangerous for human eyes.

If it hits the lens directly, it damages the nerve endings and a person can remain blind.

The laser beam is blinding even at a distance of 100 m, so it is important to be aware of where you point it. Remember that you are responsible for the health of those around you while such a device is in your hands!

Figure 3. Microcircuit LM-317.

Before starting work, you need to know that the laser diode can be damaged not only by careless handling, but also by voltage drops. This can happen in a matter of seconds, which is why diodes operate on a constant source of electricity. When the voltage rises, the LED in the device exceeds its brightness norm, as a result of which the resonator is destroyed. Thus, the diode loses its ability to heat, it becomes an ordinary flashlight.

The crystal is also affected by the temperature around it; when it falls, the laser performance increases at a constant voltage. If it exceeds the standard rate, the resonator is destroyed according to a similar principle. Less commonly, the diode is damaged by sudden changes, which are caused by frequent switching on and off of the device for a short period.

After removing the crystal, it is necessary to immediately tie up its ends with bare wires. This is to create a connection between its voltage outputs. A small capacitor of 0.1 μF with negative polarity and 100 μF with positive polarity must be soldered to these outputs. After this procedure, you can remove the wound wires. This will help protect the laser diode from transients and static electricity.

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Food

Before creating a battery for a diode, it is necessary to take into account that it must be powered from 3V and consumes up to 200-400 mA, depending on the speed of the recording device. Avoid connecting the crystal directly to batteries as this is not a simple lamp. It can deteriorate even with normal batteries. The laser diode is a self-contained element that is supplied with electricity through a regulating resistor.

The power supply system can be adjusted in three ways with varying degrees of complexity. Each of them assumes feeding from a constant voltage source (batteries).

The first method involves regulation of electricity using a resistor. The internal resistance of the device is measured by detecting the voltage as it passes through the diode. For drives with a write speed of 16X, 200 mA is sufficient. With an increase in this indicator, there is a possibility of damaging the crystal, so it is worth sticking to the maximum value of 300 mA. It is recommended to use a telephone battery or AAA finger batteries as a power source.

The advantages of this power scheme are simplicity and reliability. Among the disadvantages are the discomfort with regular recharging of the battery from the phone and the difficulty of placing the batteries in the device. Moreover, it is difficult to determine the right moment to recharge the power source.

Figure 4. Microcircuit LM-2621.

If you are using three AA batteries, this circuit can be easily fitted into a Chinese-made laser pointer. The finished design is shown in Figure 2, with two 1 ohm resistors in sequence and two capacitors.

For the second method, the LM-317 microcircuit is used. This method of arranging the power system is much more complicated than the previous one; it is more suitable for stationary type of laser systems. The circuit is based on the manufacture of a special driver, which is a small board. It is designed to limit the electric current and create the required power.

The connection circuit of the LM-317 microcircuit is shown in Fig. 3. It will require elements such as a 100 ohm variable resistor, 2 10 ohm resistors, a 1H4001 series diode and a 100 μF capacitor.

A driver based on this circuit maintains electrical power (7V) regardless of power supply and ambient temperature. Despite the complexity of the device, this circuit is considered the easiest to assemble at home.

The third method is the most portable, making it the most preferred of all. It supplies power from two AAA batteries, maintaining a constant voltage level to the laser diode. The system retains power even when the battery level is low.

When the battery is completely discharged, the circuit will stop functioning, and a small voltage will pass through the diode, which will be characterized by a weak glow of the laser beam. This type of power supply is the most economical, with an efficiency of 90%.

To implement such a power system, you will need an LM-2621 microcircuit, which is located in a 3 × 3 mm case. Therefore, you may encounter certain difficulties during the period of soldering parts. The final size of the board depends on your skill and dexterity, since the parts can even be placed on a 2 × 2 cm board. The finished board is shown in Fig. 4.

The choke can be taken from a conventional power supply for a stationary computer. A wire with a cross section of 0.5 mm is wound on it with a number of turns up to 15 turns, as shown in the figure. The choke diameter from the inside will be 2.5 mm.

Any Schottky diode with a 3A value is suitable for the board. For example, 1N5821, SB360, SR360 and MBRS340T3. The power going to the diode is adjusted by a resistor. It is recommended to connect it with a 100 ohm variable resistor during the setup process. It is best to use a worn out or unnecessary laser diode when performing a functional test. The current power indicator remains the same as in the previous diagram.

Once you have found the most appropriate method, you can upgrade it if you have the necessary skills. The laser diode must be placed on a miniature heat sink so that it does not overheat when the voltage rises. After completing the assembly of the power system, you need to take care of installing the optical glass.

Modern lasers are gradually gaining popularity and every day more and more people are added to the number of their connoisseurs. How not to get lost in the variety of choices and get exactly what you need? Is the laser pointer green or red? Simple or more powerful? With a metal housing or a plastic one? Let's try to answer all these questions in order.

Power.

The concentration and length of the laser beam depends on the power of the laser. The more powerful the laser, the further you can shine it and the less likely it is that the beam will be scattered at a great distance.

There are several types of pointers in terms of power - 50, 100, 200, 300, 500 and 1000 milliwatts. Other options are rarely used. You need to understand that the cost of the device also depends on this parameter - the more powerful it is, the more expensive it is.

More powerful pointers are suitable for creating laser shows and amateur holography, in addition, with the help of such lasers of a certain radiation spectrum, you can set fire to distant objects - for example, matches - or melt cellophane, plastic.

Beam color.

The most common are green laser pointers, which are distinguished by excellent beam visibility - the fact is that the green spectrum of the glow is best perceived by human eyes. But there are other models that have different properties and specific application.

The beam of purple pointers is practically invisible either in the dark or in the light. But such a laser makes the illuminated objects fluoresce - emit their own glow.

Red pointers at high operating powers can heat and ignite objects at a distance.

Blue, yellow and cyan lasers are used for laser shows as unusual "additions" to more common laser pointers.

Remember - its cost also depends on the color of the laser. The most expensive are yellow, blue and violet lasers, red lasers are much more affordable, and green lasers are considered the cheapest due to their widespread availability.

Other characteristics.

When choosing a laser pointer, you should pay attention to some other properties of the product. These are, first of all:

The presence of attachments. With the help of an optical attachment, you can scatter the beam and turn it into a certain image, which will be changed by rotating the attachment. It looks very spectacular! It is better if there are several such attachments.

Housing. It must be shockproof - made of special plastic or metal.

Additional elements. A hand rope and a belt pouch will protect your pointer from premature failure and excessive clogging.

Remember - using a green laser pointer, as well as purple, red, can cause serious damage to the retina! Use the devices with care and keep them out of the reach of children!

Laser - acronym for L ight A mplification by S timulated E mission of R adiation, which literally translates as "amplification of light by stimulated emission" is a device that converts the pumping energy into the energy of a narrowly directed radiation flux.

There are many different types of lasers. They can be divided into groups according to the pump source, working fluid, and field of application. Because In this article, lasers will be considered in the context of the safety of working with laser levels and rangefinders, then attention will be paid to such parameters as working wavelength (nm) and radiation power (mW).

Wavelength if it is in the visible range, determines the color of the laser beam. Radiation power determines the brightness of the beam, certain possibilities (aiming, demonstration of optical effects, reading barcodes, cutting and welding materials, laser surgery, pumping other lasers).

Radiation in laser levels and rangefinders works like a conventional laser pointer - a portable generator of coherent and monochromatic electromagnetic waves in the visible range in the form of a narrow beam. It is made on the basis of a red laser diode, which emits in the range 635-670 nm... Their radiation power does not exceed 1.0 mW.

There are several classifications of laser hazards, which, however, are quite similar. Below is the most common international classification.

Class 1 Lasers and laser systems of very low power, which are not capable of creating a radiation level hazardous to the human eye. Emission class 1 systems do not pose any danger, even with long-term direct observation with the eye. Class 1 also includes laser devices with a laser of higher power, which are reliably protected from the beam going out of the housing.

Class 2 Low-power visible lasers capable of causing damage to the human eye when specifically looking directly into the laser for an extended period of time. These lasers should not be used at head level. Invisible lasers cannot be classified as Class 2 lasers. Class 2 typically includes visible lasers up to 1 mW.

Class 2a Class 2a lasers and laser systems, positioned and secured so that the beam cannot enter the human eye when used correctly

Class 3a Lasers and laser systems with visible radiation, which usually do not pose a hazard when viewed with the naked eye only for a short period (usually due to the blink reflex of the eye). Lasers can be dangerous when viewed through optical instruments (binoculars, telescopes). Usually limited to 5 mW. In many countries, devices of higher classes in some cases require special permission for operation, certification or licensing.

Class 3b Lasers and laser systems that are hazardous when viewed directly into the laser. The same applies to the specular reflection of the laser beam. A laser is classified as class 3b if its power is more than 5 mW

Class 4 High power lasers and laser systems capable of causing severe damage to the human eye with short pulses (< 0,25 с) прямого лазерного луча, а также зеркально или диффузно отражённого. Лазеры и лазерные системы данного класса способны причинить значительное повреждение коже человека, а также оказать опасное воздействие на легко воспламеняющиеся и горючие материалы

Requirements for design and technical characteristics, rules for safe work and methods of protection against laser radiation on the territory of the Republic of Belarus are regulated by SanPiN 2.2.4.13-2-2006 "Laser radiation and hygienic requirements for the operation of laser products" and STB IEC 60825-1-2011 "Safety laser products. Part 1. Equipment classification and requirements "- the national standard of the Republic of Belarus, which is identical to the international IEC standard.

A significant part of the laser technology produced in the world is produced and labeled in accordance with the standards published by the American organization "Center for Devices and Radiological Health" (CDRH).

Laser levels and rangefinders are laser class 2 in accordance with this classification, which allows them to be used with the following precautions:
- do not look into the laser beam, the laser beam may damage your eyes, even if you look at it from a long distance;
- do not direct the laser beam at people or animals;
- the laser must be installed above eye level;
- use the device only for measurements;
- do not open the device;
- keep the device out of the reach of children;
- do not use the device near explosive substances.

The arrangement of green beams is more complicated: the first laser, infrared, with a wavelength of 808 nm, shines into the Nd: YVO4 crystal - laser radiation with a wavelength of 1064 nm is obtained. It hits the "frequency doubler" crystal - and it turns out 532 nm.

Some lasers have an infrared filter, but this significantly increases the price of the device, which means it can only be present in expensive models. It is also worth noting that green diodes, devices that emit a green beam, are much more expensive to manufacture (several times due to the greater number of rejects compared to red). And the working life of the green diode is much lower. In total, this is reflected in the final cost of the laser level. The result is the following picture. A laser level with a green beam builds projections that are better visible, the resource of such a device is lower, the cost is higher (sometimes one manufacturer for the same models differing only in a laser sets a price that differs by 1.5-2 times).

It should be noted that according to the characteristics declared by the level manufacturers, the power of such a laser is up to 2.7 mW(in red up to 1.0 mW), and safety by class 3(red 2).

To summarize, green laser really is better seen in daylight conditions than red, but we must not forget that it much more unsafe and unreasonably expensive .

This is a portable device in which there is an emitter that generates coherent and monochromatic electromagnetic waves in the visible range in the form of a beam. A laser diode (the design is much simpler) or a full-fledged solid-state laser (the design is more complicated) can be used as an emitter.

There are several types of laser pointers, which differ in color and, accordingly, in the type of emitter:

• Red
• Green
• Blue
• Turquoise
• Blue
• Purple
• Yellow
• Orange

How does a laser pointer work?

Red laser pointers

The cheapest and therefore the most common. Powered by a conventional button cell battery. This pointer works on the basis of a red laser diode, the radiation spectrum of which is 650-660 nm. In addition to the diode, a driver board is installed in the pointer, which controls the power supply. In order for the radiation to propagate in the form of a narrowly directed beam, a convex lens on both sides (or a plano-convex, flat side to the diode) is used. This lens is called a collimator.

The power of red laser pointers is usually low and for most of the items found on the market is 1-100 mW. An unpleasant feature of pointers based on red laser diodes is that these diodes quickly "burn out", which leads to a decrease in the radiation intensity. Therefore, after a few months of use, any pointer of this type shines much worse than a new one, regardless of the battery charge.

Green laser pointers

During the daytime, the human eye is much more sensitive to green than to red (about 6-10 times). Therefore, green pointers shine much brighter. True, this ratio changes at night, and here already green pointers do not have such an advantage in laser brightness over red ones.

Because green laser diodes are very expensive, diode-filled solid state lasers (DPSS) are used to create green laser pointers. They are cheaper than green laser diodes, although more expensive than red ones. The wavelength of the green laser pointer is 532 nm, the efficiency is approximately 20% (higher than that of the red one). Green pointers are more energy intensive than their red counterparts. Therefore, it is quite difficult to buy such a unit powered by a button cell battery.

Blue laser pointers

Produced not so long ago (since 2006), the principle of operation is similar to the green ones. Wavelengths - 473 nm for turquoise, 445 - for blue. There are also blue pointers with a wavelength of 490 nm. As in the green ones, a solid-state laser is used as an emitter, although there are models based on blue laser diodes (445 nm). Blue lasers are very expensive, diodes are cheaper, but they are not widely used yet. The radiation from blue laser pointers is very dangerous to the eye, therefore precautions must be taken when working with them. The efficiency is low and is about 3%.

Yellow laser pointers

The radiation wavelength of yellow pointers is 593.5 nm. There are also their orange "brothers" with a wavelength of 635 nm. In terms of its effect on the human eye, yellow is close to red, i.e. much safer than blue and green. The efficiency of the yellow pointers is very low and barely exceeds 1%.

Purple laser pointers

These pointers use violet laser diodes with a wavelength of 400-410 nm. This number is near the limit of the human eye's range, so the light from the purple pointer appears very dim. However, you should not shine a purple pointer (like any other) in the eyes, as this is harmful to them in any case.

The light from the violet pointer can cause fluorescence, during which the brightness of the glowing objects is much higher than that of the laser itself. Serial production of laser pointers began after the advent of Blu-ray optical drives, since they used laser diodes with a wavelength of 405 nm.

Laser pointer device, video