In the solid-state laser, light is normally used as the pump resource, and the crystal or glass that can create the laser is called the laser working material. The working product of the laser consists of two parts: the matrix and the turned-on ions. Matrix material offers an appropriate existence as well as a working environment for activated ions, which also complete the laser generation process. The typically used turning-on ions are generally transitional metal ions, such as chromium and ruby, as well as nickel plasma and also rare earth steel ions, such as neodymium ions. A mirror covered with a dielectric film is utilized as a resonator lens, one of which is an all-mirror and the other is a semi-mirror. Various wavelengths of laser will be emitted when utilizing various activation ions, different substrate materials, and various wavelengths of light excitation.
The following is a brief introduction of gain media YAG crystal, Ti:Sapphire crystal, ruby crystal.
YAG gain medium
YAG is short for Yttrium aluminum garnet, which is the current laser crystal matrix with the most outstanding thoroughness.
After including neodymium (Nd), it can emit 1064 nm light, and the optimum constant output power can get to 1000 w. Early use of an inert gas strobe as a laser pump source was possible, but the strobe pump setting, broad spectral array, and laser gain medium absorption range overlap were poor, as well as the large warmth lots, causing a reduced photoelectric conversion price. So currently, using the LD (laser diode) pump can accomplish high performance, high power, and a long life of the laser. The Nd:YAG laser can treat hemangiomas and also prevent tumor growth. Nevertheless, the thermal damage to the cells brought on by this laser is non-selective. While coagulating the capillaries in the tumor, the excess energy will also damage the surrounding normal tissues, leaving scars after surgery. As a result, the Nd:YAG laser is more commonly used in surgical procedures, gynecology, and ENT, but less so in dermatology.
Yb:YAG, Ytterbium (Yb) mixed in YAG, can emit 1030 nm light. Yb:YAG pump wavelength of 941 nm as well as result wavelength extremely near to pump quantum efficiency can achieve 91.4%, with the heat produced by the pump suppressed to 10% or much less (a lot of the power input right into the result of laser power, a few become hot, indicates that the conversion effectiveness is really high), is an Nd: YAG 25% ~ 30%. Yb: YAG has turned into one of the most eye-catching solid-state laser media. LD pumped high power Yb:YAG solid-state lasers have emerged as a new research hotspot and an important direction for developing effective and high-power solid-state lasers.
Other ions doped YAG
In addition to the above two kinds, YAG can be integrated into holmium (Ho), Erbium (Er), etc. Ho:YAG can produce 2097nm and also 2091nm lasers that are secure for human eyes as well as are generally appropriate for optical communication, radar and also clinical applications. Er:YAG outcomes 2.9 μm light. The human body has a high absorption price of this wavelength, which has great application possibility in laser surgical treatment and vascular surgical procedure.
Ruby gain medium
The laser wavelength of the ruby laser is 694.3 nm, and the photoelectric conversion cost is only 0.1%. Nonetheless, its long fluorescence life contributes to power storage and can result in high pulse height power. The laser created by a ruby pole with a pen lead’s density and the finger’s size can easily be produced and punched with the iron sheet. Prior to the more effective YAG laser’s advent, ruby lasers were widely utilized for laser cutting and boring. Furthermore, because the 694nm light is easily absorbed by melanin, the ruby laser is also used to treat pigmentary sores (skin spots).
Ti:Sapphire gain medium
As a result of its crystal residential properties, the titanium sapphire laser has a wide tunable array (tunable wavelength array). It can produce light with a 660–1200 nm wavelength as needed. Paired with the maturation of frequency doubling technology (which can increase the frequency of light, i.e. halve the wavelength), the Ti: Sapphire wavelength array can be included 330nm-600nm. Titanium sapphire laser has been used in femtosecond splitting, nonlinear optical study, white light generation, terahertz wave generation, etc, and also has additionally been used in clinical appeal.