Passive Q switch crystals

A passive Q switch is a tool that can achieve Q switching by benefiting from the truth that the passage of optical product depends on the laser strength at a certain wavelength. The laser freeze linker mostly creates saturated absorptive crystals in passive Q switch crystals. The absorption coefficient of saturated absorption crystal reduces with the increase of occurrence light intensity. When the saturation worth is reached, the loss (Q worth) in the laser tooth cavity is modulated, and the pulse is discharged.
Some passive Q-switching crystals are listed here:

Co: Spinel passive Q switch crystal

Co: Spinel Q switch crystals, named cobalt spinel, is a newly developed material. Its producing wavelength range is 1.2-1.6 μm, which has actually shown to be a very reliable passive Q-switched switch. It is commonly 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 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 diode laser pumps) without tooth cavity concentrating. The minimal ecstatic state absorption results in a high comparison ratio of the Q switch. That is, the ratio of the initial to saturated soaked up signal is higher than 10.

The major qualities of Co: Spinel crystal:

  • 1.3 to 1.6 mu m within the scope of the reduced optical loss
  • High damage limit

Main applications of Co: Spinel crystals: passive q-switched @ 1.54 microns.

V: YAG Q switch crystal

V: YAG crystal, the Chinese name vanadium-doped yttrium aluminium garnet, is a relatively brand-new crystalline material. Suitable for 1.06 ~ 1.44 μm laser discharge, particularly for 1.3 μm Nd laser. The absorption optimal cross-section of the ecstatic state is not evident near the absorption top of 1300 nm. This material has superb optical, mechanical as well as thermal homes. It can be generated by the Czochralski method. Vanadium-doped yttrium aluminium garnet crystals can be utilized in Nd: YAG, Nd: YAP, Nd: KGW, Nd: YVO 4 and also various other energetic media to get the passive Q-switched laser with small framework and excellent performance.

V: YAG crystal Main qualities:

  • High-ground state absorption
  • Not evident thrilled state absorption
  • Q switch high contrast
  • Excellent optical buildings, mechanical properties and thermal residential properties
  • Ultraviolet immune high damage threshold

V: YAG crystal Main application:

  • Laser rangefinder
  • Laser radar
  • The passive adjusting Q laser LIBS system

Cr: YAG Q switch crystal

Cr4+: YAG crystal, Chinese name chromium doped yttrium aluminium garnet, is a perfect material for Q switching of laser (Nd: YAG and also other doping Nd or Yb) with wavelengths from 0.8 to 1,2 μm. A noteworthy feature of Cr4+: YAG is its high damage limit of 500-1000 MW/cm2. Its absorption band prolongs from 800 nm to 1200 nm and reaches its optimal at about 1060nm, with a very large cross-sectional location of absorption top.

Chromium doped yttrium aluminium garnet crystal Main features:

  • 500-1000 MW/cm2 high damage limit
  • Very secure chemical and integrity
  • Excellent thermal conductivity, long service life
  • Small passive Q switch
  • Simple to operate

Cr: YAG crystal Main application:

  • Laser range finder
  • LIBS passive tuning Q laser system
  • Need a brief pulse laser system


In 1991, it was discovered that Cr: YSO( pure tetravalent chromium collection) solid-state saturable absorbing could be made use of 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) expands from the visible area to the near-infrared region, making it a great switch for many lasers.


Cr4+: GSGG can be used as a passive Q-switch in the 1.06 μm band. Compared to the traditional Cr4+: YAG passive Q switch crystals, Cr4+: GSGG crystal has the complying with benefits:

  • In the noticeable component is transparent (calibration) and also is much more helpful to the laser light path.
  • In 1.06 mu m band have a higher absorption coefficient. At the same time, it additionally has a solid capacity for anti-irradiation.

Read more: Faraday optical isolator

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