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Birefringent Crystal
optical crystal
α-BBO
α-BBO (Barium metaborate) crystal is an excellent birefringent material with very good optical properties, and it has good transmittance from the ultraviolet to the mid-infrared region. The α-BBO cr..
Product description
α-BBO (Barium metaborate) crystal is an excellent birefringent material with very good optical properties, and it has good transmittance from the ultraviolet to the mid-infrared region. The α-BBO crystal has good internal quality and low absorption. Due to its good ultraviolet transmittance, it is widely used in high extinction ratio and deep ultraviolet laser systems, and is mainly processed into Glan polarizing prisms, polarization beam splitters, compensators, etc. The α-phase barium metaborate crystal (α-BaB₂O₄, α-BBO) is a negative uniaxial crystal, which has a large birefringence within a wide transmission range of 190 - 3500 nm. The α-BBO crystal is an excellent crystal, especially suitable for ultraviolet and high-power applications. The physical, chemical, optical and thermal properties of α-BBO are similar to those of β-BBO crystals, but due to the central symmetry of its crystal structure, α-BBO does not have nonlinear optical properties.
Main Advantages:
• High ultraviolet transmittance
• Large birefringence
• Low volume absorption rate, suitable for high-power applications
• High damage threshold
• Stable physical and mechanical properties
• Large birefringence
• Low volume absorption rate, suitable for high-power applications
• High damage threshold
• Stable physical and mechanical properties
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Crystal Structure
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Trigonal
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Transmission Range
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190 - 3500 nm
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Density
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3.85 g/cm³
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Hygroscopicity
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Low
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Mohs Hardness
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4.5 Mohs
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Coefficient of Thermal Expansion
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-9.3×10⁻⁶ /℃ (C)
-9.5×10⁻⁶ /℃ (A)
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Damage Threshold
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1 GW/cm² @ 1064 nm, 10 ns, 10 Hz (Anti-reflection coating)
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Refractive Index
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nₒ = 1.6776, nₑ = 1.5534, @ 532 nm
nₒ = 1.6579, nₑ = 1.5379, @ 1064 nm
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Sellmeier Equation (λ in μm)
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nₒ² = 2.7471 + 0.01878 / (λ² - 0.01822) - 0.01354λ²
nₑ² = 2.37153 + 0.01224 / (λ² - 0.01667) - 0.01516λ²
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Size
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The clear aperture cross-section can reach ϕ50 mm
The length can reach 40 mm
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Surface Finish
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10/5, referring to MIL-PRF-13830B standard
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Optical Axis Orientation Accuracy
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6′
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Parallelism
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20″
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Flatness
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λ/4 @ 633 nm
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Effective Aperture
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>90%
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Coating
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Anti-reflection coating or protective coating
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Bracket
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According to customer requirements
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