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Group Velocity Delay Compensators

  • Stocked and Custom Compensators Available
  • Substrate Materials Option: Calcite, Alpha-BBO crystal
  • Fit for Ultrafast Femtoseond Pulsed Lasers
  • Typical Wavelength: 800/400nm, 1030/515nm and 600/300nm
Inquire for custom product  
Code Material Wavelength Aperture Unit Price Delivery Cart
2116-001 Calcite 800/400nm 12mm $315 4 weeks
2116-002 Calcite 800/400nm 12mm $315 4 weeks
2116-003 Calcite 800/400nm 12mm $315 4 weeks
2116-004 Calcite 800/400nm 12mm $315 4 weeks
2116-005 Calcite 1030/515nm 12mm $315 4 weeks
2116-006 Calcite 1030/515nm 12mm $315 4 weeks
2116-007 Calcite 1030/515nm 12mm $315 4 weeks
2116-008 Calcite 1030/515nm 12mm $315 4 weeks
2116-009 α-BBO 600/300nm 12mm $375 4 weeks
2116-010 α-BBO 1030/515nm 12mm $315 4 weeks

The group velocity is different for different wavelength, it is called group velocity mismatch (GVM), and then a time delay is introduced between fundamental and second harmonic generated (SHG) wavelength, in order to compensate this time delay, an time delay compensator with orthogonal polarizations are often used. Calcite crystals and alpha-BBO crystals are most popular materials to make the time delay compensators. By rotation of compensators, the time delay could be adjusted, the listed delay range are based on a rotation range of +/-12°. 

Hangzhou Shalom EO offers Group Velocity Delay Compensators for femtoline lasers, with wavelength couples of 800nm/400nm, 1310nm/515nm and 600nm/300nm, made of Calcite crystals and Alpha-BBO crystals.

Common Specifications:

Materials Calcite or alpha-BBO Orientation Tolerance +/-0.5°
Flatness λ/4@633nm Transmission Wavefront Distortion λ/4@633nm
Surface Quality 20/10 S/D Parallelism <30 arc sec

Basic Properties of Calcite:

Density 2.7 g/cm3 Melting Point 730℃
Mohs Hardness 3 Transparency Range 350-2300nm
Thermal Expansion Coefficients(/℃) aa=24.39×10-6/K ac=5.68×10-6/K Refractive Index no=2.260 nε=2.142
Damage Threshold >1GW/cm2 Sellmeier Equation (λ in μm)

no2=2.69705 + 0.0192064/(λ2-0.01820) - 0.0151624λ2

ne2=2.18438 + 0.0087309/(λ2-0.01018) - 0.0024411λ2

Basic Properties of Alpha-BBO Crystal:

Transparency Range 190-3500nm Density 3.85g/cm3
Hygroscopic Susceptibility low Mohs Hardness 4.5
Damage Threshold >1GW/cm2 Sellmeler Equation(λ in μm)

no2 = 2.7471+0.01878/(λ2 -0.01822)-0.01354λ2

ne2 = 2.37153+0.01224/(λ2 -0.01667)-0.01516λ2

Group Velocity Delay Compensator α-BBO 600/300nm, Apeture 12mm, 200-500fs

Group Velocity Delay Compensator α-BBO 600/300nm, Apeture 12mm, 200-500fs

Group Velocity Delay Compensator Calcite 800/400nm, Apeture 12mm, 10-100fs

Group Velocity Delay Compensator Calcite 800/400nm, Apeture 12mm, 10-100fs

Group Velocity Delay Compensator α-BBO 1030/515nm, Apeture 12mm, 250-600fs

Group Velocity Delay Compensator α-BBO 1030/515nm, Apeture 12mm, 250-600fs