A Passive Q switch is a gadget that can attain Q switching by taking advantage of the reality that the passage of optical product depends on 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 reduces with the rise of case light intensity. When the saturation worth is reached, the loss (Q value) in the laser cavity is modulated, and the pulse is emitted.
Some passive Q-switching crystals are listed below:
Co: Spinel crystal, named cobalt spinel, is a recently developed product. Its sending out wavelength array is 1.2-1.6 μm, which has verified to be an extremely efficient passive Q-switched switch. It is widely utilized in the eye-safe Er: glass laser (1.54 µm) and has been validated in lasers with wavelengths of 1.44 µm and also 1.34 µm. Co: Mgal2o4( Co: spinel) has a high absorption cross-section, enabling Q switching of Er: glass lasers (flash as well as diode laser pumps) without dental caries concentrating. The negligible ecstatic state absorption leads to a high comparison ratio of the Q switch. That is, the proportion of the first to saturated soaked up signal is more than 10.
The primary qualities of Co: Spinel crystal:
- 1.3 to 1.6 µm within the range of the low optical loss
- High damages limit
Main applications of Co: Spinel crystals:
- Passive q-switched @1.54 μm
V: YAG crystals
V: YAG crystal, the Chinese name vanadium-doped yttrium aluminium garnet, is a relatively new crystalline material. Appropriate for 1.06 ~ 1.44 μm laser emission, specifically for 1.3 μm Nd laser. The absorption peak cross-section of the thrilled state is not obvious near the absorption height of 1300 nm. This material has superb optical, mechanical and thermal residential properties. It can be generated by the Czochralski technique. V:YAG crystals can be utilized in Nd: YAG, Nd: YAP, Nd: KGW, Nd: YVO 4 and also other energetic media to obtain the passive Q-switched laser with small structure and also superb efficiency.
Vanadium YAG crystal main attributes:
- high-ground state absorption
- not evident excited state absorption
- Q switch high comparison
- great optical homes, mechanical homes as well as thermal properties
- ultraviolet resistant high damages limit
The V: YAG crystal main application:
- Used in laser rangefinder
- Laser radar
- The passive tuning Q laser LIBS system
Cr: YAG crystals
Cr:YAG crystal, chromium doped yttrium aluminium garnet, is a suitable material for Q switching of laser (Nd: YAG as well as other doping Nd or Yb) with wavelengths from 0.8 to 1,2 μm. A remarkable feature of Cr4+: YAG is its high damages threshold of 500-1000 MW/cm2. Its absorption band prolongs from 800 nm to 1200 nm as well as reaches its top at regarding 1060nm, with a huge cross-sectional location of absorption top.
Chromium YAG crystal Highlight:
- 500-1000 MW/cm2 high damages threshold
- Very stable chemical and dependability
- Excellent thermal conductivity, lengthy service life
- Portable passive Q switch
- Simple to run
Cr: YAG crystal Main application:
- Laser range finder
- LIBS passive adjusting Q laser system
- Need a short pulse laser system.
Chromium doped YSO crystals
In 1991, it was discovered that Cr: YSO( pure tetravalent chromium collection) solid-state saturable absorbent could be used for laser applications.
In 1993, Chen et al. utilized Cr:YSO solid-state saturable absorber to successfully act upon a 694.5 nm ruby laser.
The crystal’s wide-band absorption spectrum (coming to a head at 390 nm, 595 nm, 695 nm, and 750 nm) prolongs from the visible region to the near-infrared area, making it a good switch for several lasers.
Cr4+: GSGG can be used as a passive Q-switch in the 1.06 μm band. Compared with the conventional Cr4+: YAG passive Q-switched crystal, Cr4+: GSGG crystal has the following advantages:
- In the noticeable part is clear (calibration) and also is extra beneficial to the laser light course
- In 1.06 μm band have a greater absorption coefficient. At the same time, it also has a solid capacity for anti-irradiation.
Read more: Nonlinear optical crystal