Laser medium is usually a substance that can generate laser by stimulated radiation. The specific choice of laser medium depends on the required laser wavelength, power requirements and application fields. Solid laser medium: for example, crystal or glass doped with rare earth ions (such as Nd3+ and Er3+). ) can be used as solid laser medium. After these rare earth ions are excited by electromagnetic radiation or optical radiation, coherent lasers will be emitted around them.
Gas laser medium: For example, helium-neon laser uses helium-neon mixed gas as laser medium. Gas laser usually needs electron excitation to produce laser. Semiconductor laser medium: for example, semiconductor materials (such as gallium nitride, gallium arsenide, etc.) are used for semiconductor lasers. ) as a laser medium. Typical semiconductor lasers include laser diodes and vertical cavity surface emitting lasers (VCSEL).
These are just some common examples of laser media. In fact, there are various other laser media and corresponding laser structures. Different laser media have different characteristics and applications, so specific needs and requirements need to be considered when designing and selecting lasers.
Pump source: the laser needs to be able to provide energy for the laser medium and excite atoms or molecules in the medium to carry out stimulated radiation. Common pumping sources include laser diode, fiber laser and arc lamp. Optical resonant cavity: The optical resonant cavity is a closed space. The laser medium is placed in the cavity, and the laser is reflected back and forth in the cavity to enhance the energy and coherence of the laser. Optical resonator usually consists of concave mirror and plane mirror.
Structural expansion of laser
Laser reflector: The laser reflector consists of a high reflector and a half lens, which is used to reflect and adjust the laser beam. The high reflector reflects most of the incident light to enhance the laser power, and the half lens partially reflects the light beam and outputs the laser from the laser.
Beam shaper: The output beam of laser is often highly focused and has the characteristics of Gaussian beam. The beam shaper is used to adjust and control the spatial distribution and shape of the output beam to meet specific application requirements.