Passive Q-switch

A Passive Q-switch is a tool that can accomplish Q-switching by making the most of the truth that the passage of optical material depends on the laser strength at a certain wavelength. The laser freeze linker primarily produces saturated absorbent crystals in passive Q-switched crystals. The absorption coefficient of saturated absorption crystal reduces with the rise of incident light intensity. When reaching the saturation value, modulate the loss (Q value) in the laser cavity and send out the pulse.

Listed some passive Q-switching crystals here:

Co: Spinel

Co: Spinel crystal, named cobalt spinel, is a freshly created material. Its emitting wavelength variety is 1.2-1.6 μm, which has been confirmed to be a very effective passive Q-switched switch. It is commonly used in the eye-safe Er: glass laser (1.54 µm) and has been confirmed in lasers with wavelengths of 1.44 µm and 1.34 µm. Co: Mgal2o4( Co: spinel) has a high absorption cross-section, enabling Q switching of Er: glass lasers (flash and diode laser pumps) without cavity concentrating. The minimal fired-up state absorption produces a high contrast proportion of the Q switch. That is, the ratio of the preliminary to saturated soaked-up signal is greater than 10.

The major attributes of Co: Spinel crystal:

• - 1.3 to 1.6 mu m within the extent of the reduced optical loss
• - high damages limit

Main applications:

• - passive q-switched @ 1.54 microns

V: YAG

V: YAG crystal, the Chinese name vanadium-doped yttrium aluminium garnet, is a relatively new crystalline product. Appropriate for 1.06 ~ 1.44 μm laser emission, especially for 1.3 μm Nd laser. The absorption top cross-section of the fired-up state does not appear near the absorption top of 1300 nm. This product has excellent optical, mechanical and thermal residential properties. The Czochralski approach can produce it. V: YAG crystals can be utilized in Nd: YAG, Nd: YAP, Nd: KGW, Nd: YVO 4 and various other active media to obtain the passive Q-switched laser with the compact framework and outstanding performance.

Main features:

• - high-ground state absorption
• - not obvious excited state absorption
• - Q switch high comparison
• - great optical residential properties, mechanical residential or commercial properties as well as thermal residential properties
• - ultraviolet immune high damages threshold

Main application:

• - used in laser rangefinder, laser radar, as well as the passive adjusting Q laser LIBS system

Cr: YAG

Cr4+: YAG crystal, Chinese name chromium doped yttrium aluminium garnet, is an ideal product for Q switching of laser (Nd: YAG and other doping Nd or Yb) with wavelengths from 0.8 to 1,2 μm. A significant feature of Cr4+: YAG is its high damage limit of 500-1000 MW/cm2. Its absorption band extends from 800 nm to 1200 nm and reaches its top at 1060nm, with a large cross-sectional area of absorption height.

Main features:

• - 500-1000 MW/cm2 high damages threshold
• - highly stable chemical as well as dependability
• - great thermal conductivity, long service life
• - small passive Q switch
• - very easy to run

Main application:

• - utilized for laser range finder, LIDAR and also LIBS passive adjusting Q laser system
• - need a brief pulse laser system.

Cr: YSO

In 1991, it was found that Cr: YSO( pure tetravalent chromium collection) solid-state saturable absorptive could be utilized for laser applications.

In 1993, Chen et al. used Cr: YSO solid-state saturable absorber to efficiently act upon a 694.5 nm ruby laser. The crystal's wide-band absorption range (peaking at 390 nm, 595 nm, 695 nm, and 750 nm) extends from the visible area to the near-infrared region, making it an excellent switch for numerous lasers.

Cr: GSGG

A passive Q-switch in the 1.06 μm band can use Cr4+: GSGG. Compared with the typical Cr4+: YAG passive Q-switched crystal, Cr4+: GSGG crystal has the following advantages:
The visible component is transparent (calibration) and is extra beneficial to the laser light path, In 1.06 mu m band has a greater absorption coefficient. At the same time, it likewise has a strong ability for anti-irradiation.