Lasers in general is composed of three parts, solid-state lasers is no exception:
(1). The work of the material it is the core of lasers, only to realize the material-level transition can work as a laser material. At present, the laser has been the work of thousands of substances, laser wavelength from X Guangyuan to infrared light. Such as helium-neon laser through the assistance of helium atoms, so that the two-level atomic Ne achieve population inversion;
(2). Inspire energy (optically pumped) and its role is to work the material to energy, will soon level atoms excited by the low-energy high-energy level to the outside world energy. Through the work of such bright lights substances to achieve population inversion is called optical pumping method. For example, ruby lasers, is to use high-powered strobe lights rubies (working material) and to achieve population inversion, resulting in a laser-generated conditions. Usually light energy, geothermal energy, electric energy, chemical energy.
(3). Optical laser cavity This is an important component, and its role in the work first, so that substances carried out by Stimulated Emission of Radiation; Second, continued to accelerate photon; three is to limit the laser output direction. The simplest optical resonator is placed in the helium-neon laser at both ends of the two parallel mirrors the composition. When the number of neon atoms in achieving population inversion between the two-level transition, radiation from the direction parallel to the laser photons, these photons will be back and forth between the two mirror reflection, so he constantly caused by stimulated emission of radiation, quickly produce a very strong laser. These two parallel mirrors, a reflectivity close to 100%, or totally reflective. Another reflection rate is about 98 percent, laser is a mirror from the injection. Laser mainly consists of three parts: the work of the material, encouraging energy, resonator (cavity). Figure: The basic structure of ruby laser.
- Solid-state lasers generally use the optical excitation source. Work for the mixed material and impurity elements in crystal or glass. The most common solid-state lasers have ruby lasers, neodymium glass laser, neodymium-doped YAG lasers, solid-state lasers output energy high, small and strong, in laser processing, laser weapons have important applications.
Laser Q-basic principles
Q-technology is adopted in one way or another so that cavity Q value over time in accordance with certain procedures for changing technology. In the pump chamber at the beginning so that low-Q state, that is, raising the oscillation threshold, so that oscillation can not be generated, the level of inversion few particles accumulated on the large scale, when accumulated to a maximum value (saturation value), the sudden reduce wear and tear so that cavity, Q value of the sudden increase in laser oscillation quickly set up, in very short period of time reversal level particle number is consumed, into the cavity light energy output in the cavity of a single pulse form of the energy released, they received a very high peak power pulsed laser output giant.
The following brief Q-electro-optic crystal works. YAG crystal in the xenon lamp light pump launch natural light through the prism of post-polarization into line along the x direction of polarized light, if not crystal modulation voltage, light along the optical axis through the crystal, its polarization state is not changed by the whole mirror reflection again (no change) through the crystal and polarization modulation prism, electro-optic Q switch in the "open" state. If the crystal on the applied voltage modulation, as a result of vertical electro-optical effect, when the direction of the line along the x-polarized light through the crystals, after all-mirror reflection to come back again after a modulated crystal, polarized incident light deflection physiognomy for the 900, polarized light can not through the prism of polarization, Q switch in the "off" state. If we dare to the beginning of xenon lamps lit, the crystals on the prior re-modulation voltage, so resonant cavity in the "off" low-Q state, blocking the formation of laser oscillation. Question-level laser particle inversion to the maximum number of accumulated suddenly dropping the crystal on the voltage, so that laser instantaneous state at high Q value, resulting in flooding-style laser oscillation, you can output a giant pulse.
