Crystals Materials
KTP Crystal for Optical Parametric Oscillation (OPO) and SHG@1064nm to 532nm applications
  • High nonlinear coefficient (DEFF)
  • High laser damage threshold
  • Wide transparency range from 350 nm to 4.5 µm
  • Broad angular acceptance and small dispersion angle
  • Broad type I and II non-critical phase-matching range
  • Great mechanical stability
  • Nonhygroscopic crystal
  • KTP crystal (KTiOPO4 or Potassium titanyl phosphate) is a nonlinear optical material commonly appilication for frequency doubling of Nd:YAG lasers and other Nd-doped lasers, particularly at a low or medium-power density.

    KTP crystal exhibits a high optical quality, broad transparency range, wide acceptance angle, small walk-off, and type I and II non-critical phase-matching (NCPM) in a wide wavelength range. KTP crystal has a relatively high effective SHG coefficient (about 3 times higher than that for KDP) and fairly high damage threshold (>500 MW/cm²).

    KTP nonlinear crystals can be used as a nonlinear OPO medium for IR generation up to 4 µm and used as a pump source for mid-IR nonlinear crystal-based optical parametric oscillators, such as ZGP OPO

    Specifications of KTP Crystal
    Thickness 3 mm ~ 150 mm or Upon customer request
    Thickness/Diameter Tolerance ±0.05 mm
    Orientation Tolerence < 0.5°
    Surface Quality 10/5 S/D per MIL-O-13830A
    Parallelism < 10 arcsec
    Perpendicularity < 5 arcmin
    Clear Aperture > 90%
    Wavefront Distortion λ/8 @ 633 nm
    Surface Flatness < λ/8 @ 632.8 nm
    Chamfer < 0.1 mm @ 45°
    Coating AR/HR/PR coating upon customer's request
    Physical and chemical properties
    Chemical Formula KTiOPO4
    Crystal Structure Orthorhombic, space group Pna21,point group mm2
    Lattice Constant a=6.404Å, b=10.616Å, c=12.814A, Z=8
    Density 3.01 g/cm3
    Melting Point About 1172°C
    Refractive indices nX = 1,7404
    nY = 1,7479
    nZ = 1,8296 @1064 nm
    Hardness (Mohs) 5
    Thermal Conductivity 13W/m/K
    Thermal Expansion Coefficients ax=11x10-6/℃
    Optical and Nonlinear properties
    Transparency Range 350 nm ~ 4500 nm
    SHG Phase Matchable Range 497 ~ 1800 nm (Type II)
    Therm-optic Coefficient (/℃, λ in μm) dnx/dT=1.1*10-5
    Absorption Coefficients < 0.1%/cm at 1064 nm
    < 1%/cm at 532 nm
    Angle Acceptance 14.2 mrad·cm (φ); 55.3 mrad·cm (θ) for Type II SHG of a Nd:YAG laser at 1064 nm
    Temperature Acceptance 24°C·cm for Type II SHG of a Nd:YAG laser at 1064 nm
    Spectral Acceptance 0.56 nm·cm for Type II SHG of a Nd:YAG laser at 1064 nm
    Walk-off Angle 0.55° for Type II SHG of a Nd:YAG laser at 1064 nm
    NLO Coefficients deff(II)≈(d24 - d15)sin2Φsin2θ - (d15sin2Φ + d24cos2Φ)sinθ
    Relative Dielectric Constant εeff=13

    Stock specification list

    If need other specifications and quantities products, please contact us(
    Part Number Size Theta, θ Phi, φ Coating S1/S2 Application
    KTP-Cry-001 3x3x5 mm 90 23.5 AR/AR@1064+532 nm SHG@1064 nm
    KTP-Cry-002 3x3x10 mm 90 23.5 AR/AR@1064+532 nm SHG@1064 nm
    KTP-Cry-003 7x7x9 mm 90 23.5 AR/AR@1064+532 nm SHG@1064 nm


  • AR/HR/PR coatings are available at your specified wavelength.
  • Be sure to wear laser safety goggles when checking optical path and adjusting optical axis.
  • KTP is relatively soft and therefore requires precautions to protect its polished surfaces.
  • When angle adjusting is necessary, keep in mind that the acceptance angle of KTP is small.
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