The pointer of the laser pointer is not a toy! The course was taken home to an elementary school area in Wisconsin in the fall of 1996. A 16-year-old girl was used as a prank laser pointer, illuminating her eyes. She experienced two brief exposures, one during the pom pom program and the other while walking in the corridor. She reported these incidents to her parents and added that after the first exposure, everything looked green. After a second, she was temporarily unable to see from her right eye.
Unfortunately, arsenic is also used to make countless red LEDs and edge-emitting lasers, which cannot emit light with much shorter wavelengths. The obvious solution for making blue and green VCSELs is to replace nitride with nitride-a material system used to make blue and green LEDs and edge-emitting lasers. All teams developing blue and green VCSELs have adopted this method, but it has certain disadvantages. In particular, the refractive indices of nitrides are relatively similar. Therefore, about twice as many layers are required to obtain a mirror with sufficient reflection, which results in an excessively long time for growing the entire device structure.
But in fact, heat is not a problem in normal use. Do you really want to turn on the laser engraving machine and keep it there? Laser sight guns are best used with relatively fast switch activation methods. Tactically speaking, you will not often turn on the laser to search, because this will make your location lose potential threats. Unless you plan to clean up igloos in the Arctic Circle, sensitivity to cold weather is not so important.
It took several years to produce the first VCSEL with an output power of 1 mW or higher, and more innovations were made. Sony announced this milestone in 2016 and adopted a 1.1 mW blue VCSEL. The production process is first to form dielectric mirror islands, then grow GaN material between them, and finally deposit cavities. After that, a second dielectric mirror was added.
Nichia’s design has created a new situation and completely abandoned the nitride objective lens. However, whether this makes VCSEL manufacturing easier remains to be seen. After the cavity grows, it must be removed from the substrate that lays the foundation for its growth. Then, Nichia still insists on the design. In 2009, engineers announced that the output of the blue laser pointer would be changed from sapphire to GaN. 0.14 mW increased to 0.62. mW. This change has improved material quality and reduced defects by three orders of magnitude.