Cr4:YAG Passive Q-Switch Crystals

Cr4:YAGCr4+:YAG crystals have several advantages when compared to traditional Passive Q-switching choices such as organic dyes and colour centres materials. Crystal Passive Q-switch is preferred for simplicity of manufacturing and operation, low cost, and reduced system size and weight.   Cr4+:YAG is chemically stable, UV resistant and it is durable. Cr4+:YAG will operate over a wide range of temperatures and conditions. The good thermal conductivity of Cr4+:YAG is well suited for high average power applications.

Excellent results have been demonstrated using Cr4+:YAG as a passive Q-switch for Nd:YAG lasers. The saturation fluence was measured to be approximately 0.5 J/cm2. The slow recovery time of 8.5 µs, as compared to dyes, is useful for the suppression of mode locking. Q-switched pulsewidths of 7 to 70 ns and repetition rates of up to 30 Hz have been achieved. Laser Damage Threshold tests showed AR coated Cr4+:YAG passive Q-switches exceeded 500 MW/cm2.

The optical quality and homogeneity of Cr4+:YAG is excellent. To minimise insertion loss the crystals are AR coated. Cr4+:YAG crystals are offered with a standard diameter, and a range of optical densities and lengths to match your specifications.

Optical Properties and Dimensions

Diameter 6.35 mm
  0 mm / +0.05 mm
Typical Length 2 mm to 10 mm
Parallelism 30 arc-sec. max
Flatness λ/2 at 632 nm Max.
Refractive Index 1.82 at 1.064µm
Standard Optical Densities 0.40 +/- 10%
  0.50 +/- 10%
  0.60 +/- 10%
  1.00 +/- 10%
Saturation Fluence near to 0.5 J/cm2
Recovery Time 8.5 µs
Repetition Rate > 30 Hz
AR coating 0.3% per surface
Damage Threshold > 500 MW/cm2
Chemical Formula Y3Al5O12:Cr4+
Orientation <111 > cubic