Crystals Materials
KYW Crystals for raman lasers and laser radiation frequency tuning applications
  • Broad transparency range from 350 nm to 5.5 μm
  • Two large Raman shifts of 765 cm-1 and 905 cm-1
  • Surface Quality: 10/5 Scratch/Dig MIL-O-1380A
  • Parallelism: < 10″
  • Perpendicularity: < 5'
  • Clear Aperture: > 90%
  • Surface Flatness: < λ/10 @ 632.8 nm
  • Coating: AR/HR/PR coating upon customer's request
  • Quality Warranty Period: One year
  • Potassium yttrium tungstate (KY(WO4)2, KYW) crystals offer two strong phonon modes around 765 cm-1 and 905 cm-1, which have similar Raman gain and are pump polarization dependent. KYW crystals possess good mechanical properties, high optical damage threshold, broad transparency range (350 nm - 5,5 µm), and thermal conductivity around three times higher than barium nitrate.

    Specifications of KYW Crystal
    Orientation b-cut
    Clear aperture >90%
    Face dimensions tolerance +0.0/-0.1 mm
    Length tolerance ±0.1 mm
    Parallelism error <20 arcsec
    Perpendicularity error <10 arcmin
    Protective chamfers <0.1 mm at 45˚
    Surface quality 10-5 S-D
    Surface flatness <λ/8@632.8 nm
    Wavefront distortion <λ/4@632.8 nm
    Coatings AR(R<0.7%)@500-650 nm
    Laser-induced damage threshold >10 J/cm2@1064 nm, 10 ns
    Mount Unmounted
    Physical and optical properties
    Property Value
    Chemical formula KY(WO4)2
    Crystal structure Monoclinic, C2/c
    Lattice parameters a = 10.64 Å, b = 10.32 Å, c = 7.55 Å
    Density 6.61 g/cm3
    Mohs hardness 4-5
    Transparency range 0.35-5.5 μm
    Refractive indices (1064 nm, room temperature) np = 1.9688, nm = 2.0065, ng = 2.0507
    Thermal conductivity (average value) 3.3 Wm-1K-1
    dn/dT dnp/dT=-14.6 × 10-6 K-1, dnm/dT=-8.9 × 10-6 K-1, dng/dT=-12.4 × 10-6 K-1
    Raman frequency shift (T = 300 K) 905 cm-1 (E||Nm), 765 cm-1 (E||Ng)
    Raman gain (1064 nm pump, steady-state regime) 3.6 cm/GW

    Stock specification list

    If need other specifications and quantities products, please contact us(
    Part Number Face size Length Doping Coating
    KYW-Cry-001 5.0*5.0 mm 15.0 mm undoped UnCoated
    KYW-Cry-002 5.0*5.0 mm 50.0 mm undoped AR/AR@450-800 nm


  • Anti-reflection coatings are available at your specified wavelength.
  • Be sure to wear laser safety goggles when checking optical path and adjusting optical axis.
  • To inquiry or order a finished KYW laser rod, please specify the specification listed above, for common application, we only need to know the main specification: Nd-dopant concentration, sizes, and coating. For special request, please specify specification in details for evaluation and fabrication.
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