Detailed explanation of the principle of five laser pens

Laser pen, also known as laser pen, star pen and so on. , is a pen-type transmitter which designs visible laser as portable and easy to hold, and is processed by laser module (light emitting diode). Common laser indicators are red light (λ = 650 ~ 660 nm,? 635nm), green light (λ=5 15-520nm,? 532nm), blue light (λ = 445 ~ 450 nm) and blue-violet light (λ=405nm). So, what is the principle of laser pen? Let's have a look.

Introduction of laser pen:

Laser pen, also known as laser pen, star pen and so on. , is a pen-type transmitter which designs visible laser as portable and easy to hold, and is processed by laser module (light emitting diode). Common laser indicators are red light (λ = 650 ~ 660 nm,? 635nm), green light (λ=5 15-520nm,? 532nm), blue light (λ = 445 ~ 450 nm) and blue-violet light (λ=405nm).

It is usually used by reports, teaching and tour guides to project a light spot or a beam of light to objects, but it is not suitable for use in specific places, such as art galleries (some paintings are afraid of light) and zoos.

Improper use of laser pointer may cause serious damage to retina and even blindness, which is not suitable for children.

What is the principle of laser pointer?

Early laser pens used He-Ne (HeNe) gas laser with wavelength of 633 nm, which was usually used to generate laser beams with energy less than 1mW. The cheapest laser pen uses a crimson laser diode with a wavelength close to 670/650nm. The more expensive one uses a red-orange diode with a wavelength of 635nm, which is easier for human eyes to recognize. There are other colors of laser pens, the most common being green light with a wavelength of 532nm.

The principle of red laser pointer

Because there is a laser diode that produces this wavelength, its structure is the simplest, basically just a battery-powered diode. The red laser pointer first appeared in the1980s. It is a huge and bulky device worth hundreds of dollars. It's small and cheap. In recent years, a diode-pumped solid-state laser with the wavelength of 67 1nm has appeared. (DPSS) red laser pointer. Although this wavelength can be obtained by cheap diode, DPSS technology can produce laser with higher quality and narrower frequency band.

The principle of yellow laser pointer

A yellow laser pen with a wavelength of 593.5nm appeared on the market. Based on DPSS technology, two laser beams with wavelengths of 1064nm and 1342nm are added by a nonlinear crystal to obtain two laser beams. The complexity of this process makes the yellow laser pen unstable and inefficient. The output power varies with temperature in the range of 1 ~ 10 MW, and mode jump will occur when it is overheated or undercooled. This is because the size of the laser pen cannot provide the required temperature stability and cooling components. In addition, most 593.5 nm laser pens work in pulse mode, so that smaller pump diodes can be used.

Principle of green laser pointer

The nonlinear crystal is excited by an infrared laser with a wavelength of 808nm, generating infrared light of 1064nm, and then frequency doubling to generate green light of 532nm, which belongs to a solid-state laser. Some green lasers operate in pulsed or quasi-continuous mode to reduce cooling problems and extend battery life. The published green laser without frequency doubling has higher efficiency. Due to the Rayleigh scattering of atmospheric molecules, even low-power green light can be seen at night. This kind of laser pointer is often used by astronomy enthusiasts to point out the stars and constellations. The green laser pointer can have various output powers. 5mW is the safest to use and can be seen in dim light, so it doesn't need more power for pointing purposes.

The principle of blue laser pointer

At first, DPSS only had 473nm blue laser, and its power was low and unstable. With Casio's development of high-brightness projectors with mixed light sources including blue laser diodes (445nm), blue semiconductor diodes with power exceeding 1000mW (the fourth category) have become popular in mass production.

Principle of purple laser pointer

The blue-purple laser diode with the wavelength of 405nm is a semiconductor laser, which is close to the ultraviolet band and has low visibility, but it can stimulate fluorescence and has the functions of banknote inspection and chemical inspection.

The above is the introduction of the principle of various color laser pens. Only by understanding these principles can we use the laser pointer correctly. However, in the process of use, please remember not to irradiate other people's eyes with a laser pen, which will easily damage other people's retina and have a great impact on vision. Please use it with caution.

Precautions:

In addition to safety, you must also be careful when using a laser pointer. In the art gallery, because some paintings may be afraid of light, it is not suitable to use a laser pointer. In the zoo, in order to avoid scaring animals, laser pens should not be used either. Astronomy enthusiasts should pay attention when pointing at the starry sky with a laser pointer. Don't use the pointer frequently and for a long time, so as not to hinder others from watching the stars and taking pictures. In crowded public places, in order to avoid accidentally injuring others, you should stop using laser pens. Some high-power laser pens have obvious thermal effects and cannot be used continuously for a long time, especially for temperature-sensitive solid-state lasers.

Although the laser pointer is powerful, it can do a lot of impossible work. In the market, it has won unanimous praise from consumers. But you should also pay attention to safety when using it.

Therefore, when using a laser pointer, eyes, flammable items and valuables should be avoided. Safety first!

The above are the five principles of laser pen introduced by Bian Xiao, hoping to help you. For more laser pointer principles, please continue to pay attention to Tuba rabbit decoration.

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