What is a class 1 laser pointer?

Class 1 red laser pointer are harmless (safe for the eyes), and regardless of the emitted wavelength, no further measures are required except for proper marking on the device. Laser class 1M: The accessible laser radiation wavelength range is 302.5 nm to 4000 nm. In addition, which lasers are allowed? If the danger cannot be ruled out, the product is prohibited from being sold in Germany. This applies to all laser pointers with a power higher than 1mW (hazard levels 3R ​​to 4). Accordingly, only 1 to 2M laser markers can be traded in Germany.

The first condition for producing laser light is population inversion. In semiconductors, electrons in the valence band are pumped to the conduction band. In order to obtain ion number reversal, heavily doped P-type and N-type materials are usually used to form a PN junction. In this way, under the action of an external voltage, ion number reversal occurs near the junction area. At high Fermi level EFC Electrons are stored in the conduction band below, and holes are stored in the valence band above the low Fermi level EFV. Achieving population inversion is a necessary condition for laser generation, but it is not a sufficient condition.

To generate blue laser pointer light, a resonant cavity with extremely low loss is also necessary. The main part of the resonant cavity is two parallel mirrors. The stimulated radiation emitted by the active material is reflected back and forth between the two mirrors, continuously causing new The stimulated radiation makes it constantly amplified. When the stimulated radiation meets the threshold condition and resonance condition, light oscillation can be formed, and stable laser can be output.