The laser pointer, also known as the laser pen, the star pen, etc., is a pen-type transmitter that is designed to be a portable, hand-friendly,procurement high efficiency UV and IR grade optical mirrors (light-emitting diode). Common laser pointers include red light (λ = 650 to 660 nm, 635 nm), green light (λ = 515-520 nm, 532 nm), blue light (λ = 445 to 450 nm), and blue-violet light (λ = 405 nm).
It is usually used by reporting, teaching, and tour guides to project a light spot or a light pointing object, but it is not suitable for use in specific places, such as art galleries (some paintings are afraid of light), zoos, etc.
Improper use of the laser pointer may cause severe damage to the retina, macula, or even permanent blindness, and children should not use it.
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Early laser pens used a HeNe gas laser with a wavelength of 633 nanometers (nm), which is commonly used to generate laser beams with energy no more than 1 mW. The cheapest laser pointer uses a deep red laser diode with a wavelength close to 670/650 nm. A slightly more expensive is a red-orange diode with a wavelength of 635 nm, which is easier to recognize by the human eye. There are also laser pointers of other colors, the most common being green light with a wavelength of 532 nm.
In recent years, the 593.5nm yellow-orange laser pointer has also begun to appear. In September 2005, a 473 nm blue laser pointer appeared. At the beginning of 2010, a "blue-violet" laser pointer with a wavelength of 405 nm appeared.
The apparent brightness of the spot illuminated by the laser pen depends not only on the power of the plano/spherical/aspherical/cylindrical/paraboloid/off-axis optical mirrors and on the surface reflectance, but also on the color perception of the human eye. For example, since the human eye is most sensitive to green light having a wavelength of 520-570 nm in the visible spectrum, and the sensitivity to redder or bluer wavelength is decreased, green light appears brighter than other colors at the same power.
Laser pointer
Usually in mW. In the United States, lasers are classified by the American National Standards Institute and the US Food and Drug Administration (FDA). A visible light (wavelength 400-700 nm) laser pen with a power of less than 1 mW is of the second type (Class 2 or II); a power of 1-5 mW is a third type A (Class 3A or IIIa). Class 3 B (Class 3B/IIIb) lasers (power 5–500 mW) and Category 4/IV lasers (power greater than 500 mW) cannot be marketed in the name of laser pens by law.
Laser pointer red light
Since there is a laser diode that produces this wavelength, its structure is the simplest, basically only a diode that is powered by a battery. The red customizable large size optical prism first appeared in the 1980s and is a huge and bulky device worth hundreds of dollars; it is now small and cheap. In recent years, a diode-pumped solid-state laser (DPSS) red laser pointer with a wavelength of 671 nm has appeared. Although this wavelength can be obtained with inexpensive diodes, DPSS technology can produce higher quality, narrower wavelength lasers.