The laser must have the above three parts, the pump source, the working material and the optical resonant cavity, and the laser using solid laser material as the working material. The working substance undergoes population inversion distribution under the action of the pump source and becomes an active substance, which has the effect of light amplification. Part of the amplified light is fed back to participate in excitation, and the resonant cavity oscillates, and laser light can be produced after certain conditions are met.
1. Pump source: its function is to give energy to the working substance, and to excite atoms from low energy level to high energy level of external energy. Usually there can be light energy, thermal energy, electric energy, chemical energy, etc.
2. Working substance: At the core of the laser, only the substance that can achieve energy level transition can be used as the working substance of the laser.
3. Optical resonant cavity: make the stimulated radiation of the working substance go on continuously; accelerate the photon continuously; limit the direction of laser output.