KTA Crystals Specification
Length
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0.1–30mm
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Size
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<15×15×30mm
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AR Coating
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Visible up to 3300nm
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Service
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Post-polishing, post-coating
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Delivery
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10 working days for polished, 15 working days for AR-coated
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KTA Crystals Specifications
Dimensional tolerance:
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±0.1mm
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Flatness:
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λ/8 @ 633nm
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Surface quality: Scratches/Grooves
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10/5
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Parallelism:
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better than 30 arcseconds
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Perpendicularity:
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better than 30 arcminutes
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Angular tolerance:
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△< 0.5°, △< 0.5°
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AR Coating:
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AR coatings
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Clear aperture:
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>90% central area
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Transmitted wavefront distortion:
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less than λ/8 @ 633nm
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KTA Crystal Characteristics:
High non-linear optical coefficients
Broad angular bandwidth and minimal walk-off angle
Broad temperature and spectral bandwidth
High electro-optic coefficients
Lower absorption in the 3–4 µm range compared to KTP
Non-hygroscopic, chemically and mechanically stable
High thermal conductivity
High damage threshold
Properties of KTA Crystals
a. Linear optical properties:
Transmission range
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350 nm – 5500 nm
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Refractive indices: 1064nm 532nm
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nx ny nz 1.7818 1.7866 1.8680 1.8264 1.8331 1.9310
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Sellmeier equations (l in µm)
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nx2 = 1.90713 + 1.23522l2/(l2 – 0.19692) – 0.01025l2 ny2 = 2.15912 + 1.00099l2/(l2 – 0.21844) – 0.01096l2 nz2 = 2.14768 + 1.29559l2/(l2 – 0.22719) – 0.01436l2
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Thermo‐optic coefficients
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dnx/dT = 1.1×10⁻⁵/°C, dny/dT = 1.3×10⁻⁵/°C dnz/dT = 1.6×10⁻⁵/°C
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Absorption coefficient
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a < 1% cm⁻¹ at 1064nm and 532nm
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b. Non-linear optical properties:
Phase-matchable SHG range
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542 – 1800nm
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Non-linear optical coefficients
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d31 = 2.8 pm/V, d32 = 4.2 pm/V, d33 = 16.2 pm/V, d24 = 3.2 pm/V, d15 = 2.3 pm/V
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Expressions for effective non-linearity
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deff(II) = (d24 – d15) sin²f sin²q – (d15 sin²f + d24 cos²f) sinq
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Electro-optic coefficients (low frequency)
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r13 = 11.5 pm/V, r23 = 15.4 pm/V, r33 = 37.5 pm/V
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Dielectric constant
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eeff = 42
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Applications of KTA Crystals:
OPO for generating mid-infrared frequencies – up to 4 µm;
Sum and difference frequency generation in the mid-infrared range;
Electro‐optic modulation and Q‐switching.