♤Products > Optical Crystals >> α-BBO Crystal
α-BBO Crystal
Negative uniaxial α-BBO crystal is an excellent birefringent crystal, suitable for the manufacture of polarizer, polarization beam displacer, time delay compensator plate and other birefringent device, especially for UV and high power laser. Polarizer made of Alpha-BBO crystal has continuous transmission from 200nm to 3300nm. Alpha-BBO is high temperature phase crystal of Barium Borate (BaB2O4), whereas BBO NLO crystal (Beta-BaB2O4) is low temperature phase crystal of BaB2O4.
Features of α-BBO Crystal
- High optical homogeneity (< 1 × 10E-6 /cm)
- Extremely low optical absorption
- Wide transparency wavelength range (189-3500nm)
- Low hygroscopic susceptibility
- High damage threshold
Basic Properties of Alpha-BBO Crystal
Density: 3.85 g/cm³
Thermo-Optic Coefficients:
dno/dT = -9.3 × 10E-6 /K, dne/dT = -16.3 × 10E-6 /K
Optical Homogeneity: 1 × 10E-6 /cm
Damage Threshold:
3 GW/cm² @1064nm, 1 GW/cm² @532nm, 10ns
Hygroscopic Susceptibility: Low
Thermal Expansion Coefficients:
(25-900 °C) α(a) = 4 × 10E-6/ K, α(c) = 4 × 10E-6/ K
Optical Properties of α-BBO Crystal
Transparency Range: 189-3500 nm
Linear Absorption Coefficients: 0.005/cm @200-2300 nm
Refractive Indices, Birefringence and Walk-Off Angle:
ne=1.58462, no=1.65790, δn=-0.073282, ρ=4.9532° @ 1064nm
ne=1.60206, no=1.67755, δn=-0.075491, ρ=5.0407° @ 532nm
ne=1.67190, no=1.76171, δn=-0.089805, ρ=5.6926° @ 266nm
Specifications & Capability of α-BBO Crystal
2) Length: max 35 mm
3) Surface Quality: 10-5 scratch-dig
4) Beam Deviation: 20 arc second
5) Optical Axis Orientation: +/-0.5°
6) Flatness: < λ/8 @633 nm
7) Transimission Wavefront Distortion: < λ/4 @633 nm
8) Coating: upon customer's specification