Crystals Materials
KTP Crystal for Optical Parametric Oscillation (OPO) applications
  • Excellent nonlinear, electro-optical and acousto-optical properties
  • High nonlinear coefficient
  • Wide transparency range
  • Broad angular acceptance
  • Broad thermal acceptance
  • KTP crystal (KTiOPO4 or Potassium titanyl phosphate) is widely used in laboratory and medical systems, range detectors, lidar, optical communications and industrial laser systems. So far, Nd-doping crystal lasers that use KTP for intra-cavity and extra-cavity frequency doubling have gradually replaced visible dye lasers and tunable sapphire lasers. KTP crystals are advantageous due to their high nonlinearity, great mechanical stability, high optical quality, and transparency range of 350 nm - 4.5 µm.

    Specifications of KTP Crystal
    Thickness/Diameter Tolerance ±0.05 mm
    Orientation Tolerence < 0.5°
    Size 3 mm ~ 150 mm or Upon customer request
    Dimension Tolerances ±0.05 mm
    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/℃, ay=9x10-6/℃, az=0.6x10-6/℃
    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; dny/dT=1.3*10-5; dnz/dT=1.6*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@1064+532 nm/AR@1064+532 nm SHG@1064 nm
    KTP-Cry-002 3x3x10 mm 90 23.5 AR@1064+532 nm/AR@1064+532 nm SHG@1064 nm
    KTP-Cry-003 7x7x9 mm 90 23.5 AR@1064+532 nm/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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