A Passive Q switch is a tool that can attain Q switching by capitalizing on the fact that the passage of optical material depends upon the laser intensity at a certain wavelength. The laser freeze linker mostly creates saturated absorbent crystals in passive Q-switched crystals. The absorption coefficient of saturated absorption crystal decreases with the rise of case light strength. When the saturation worth is reached, the loss (Q worth) in the laser cavity is modulated, and also the pulse is emitted.
Some passive Q-switching crystals are listed here:
Cr: YAG
Cr: YAG crystal, Chinese name chromium doped yttrium aluminium garnet, is a suitable product for Q switching of laser (Nd: YAG as well as various other doping Nd or Yb) with wavelengths from 0.8 to 1,2 μm. A notable feature of Cr4+: YAG is its high damages limit of 500-1000 MW/cm2. Its absorption band prolongs from 800 nm to 1200 nm and reaches its peak at regarding 1060nm, with a large cross-sectional location of absorption height.
Cr: YAG crystal Main features:
- 500-1000 MW/cm2 high damages limit
- Highly steady chemical and also dependability
- Great thermal conductivity, long life span
- Portable passive Q switch
- Easy to operate
Cr: YAG crystal Main application:
- Utilized for laser range finder, LIDAR and LIBS passive adjusting Q laser system
- Require a short pulse laser system.
Co: Spinel
Co: Spinel crystal, named cobalt spinel, is a newly developed product. Its emitting wavelength range is 1.2-1.6 μm, which has actually proved to be a really effective passive Q-switched switch. It is widely made use of in the eye-safe Er: glass laser (1.54 µm) and also has been confirmed in lasers with wavelengths of 1.44 µm and also 1.34 µm. Co: Mgal2o4( Co: spinel) has a high absorption cross-section, making it possible for Q switching of Er: glass lasers (flash and also diode laser pumps) without cavity concentrating. The minimal ecstatic state absorption causes a high contrast ratio of the Q switch. That is, the proportion of the first to saturated absorbed signal is greater than 10.
The major characteristics of Co: Spinel crystal:
- 1.3 to 1.6 mu m within the range of the low optical loss
- High damage limit
Main applications of Co: Spinel crystals: passive q-switched @ 1.54 microns.
V: YAG
V: YAG crystal, the Chinese name vanadium-doped yttrium aluminium garnet, is a relatively brand-new crystalline product. Suitable for 1.06 ~ 1.44 μm laser discharge, specifically for 1.3 μm Nd laser. The absorption peak cross-section of the excited state is not noticeable near the absorption top of 1300 nm. This material has outstanding optical, mechanical and thermal buildings. It can be created by the Czochralski method. V: YAG crystals can be made use of in Nd: YAG, Nd: YAP, Nd: KGW, Nd: YVO 4 and other energetic media to get the passive Q-switched laser with portable structure and excellent performance.
V: YAG crystal Main qualities:
- High-ground state absorption
- Not obvious excited state absorption
- Q switch high comparison
- Excellent optical residential or commercial properties, mechanical homes and also thermal buildings
- Ultraviolet immune high damages limit
V: YAG crystal Main application: Utilized in laser rangefinder, laser radar as well as the passive adjusting Q laser LIBS system.
Cr: YSO
In 1991, it was discovered that Cr: YSO( pure tetravalent chromium series) solid-state saturable absorptive could be utilized for laser applications.
In 1993, Chen et al. made use of Cr: YSO solid-state saturable absorber to effectively act upon a 694.5 nm ruby laser.
The crystal’s wide-band absorption range (coming to a head at 390 nm, 595 nm, 695 nm, and 750 nm) expands from the noticeable area to the near-infrared region, making it a great switch for lots of lasers.
Cr: GSGG
Cr4+: GSGG can be utilized as a passive Q-switch in the 1.06 μm band. Compared to the standard Cr4+: YAG passive Q-switched crystal, Cr4+: GSGG crystal has the adhering to benefits:
- In the visible component is transparent (calibration) and also is extra useful to the laser light path.
- In 1.06 mu m band have a better absorption coefficient. At the same time, it likewise has a strong capability for anti-irradiation.
