Undoped monoclinic KGd(WO4)2 KGdW KGW

Undoped monoclinic KGd(WO₄)₂ (KGdW)

We can grow crystals with aperture up to 50x50mm2 and 50-70mm length.
Request a price for the KGW element 5x5x50mm, b-cut, AR/AR-coated @1064+1180nm

Property	Value
Crystal structure	Monoclinic centrosymmetric (C⁶_2h-2/m)
Site symmetry / Coordination number / Gd³⁺ ionic radius	C₂ / 8 / 0.938 Å
Temperature of the polymorphic transformation / melting	1005°C / 1075°C
Crystallographic setting	C2/c or I2/c (a₁ = a+c, b₁ = b, c₁ = –c)
Unit-cell parameters	a=10.652(4)Å, b=10.374(6)Å, c=7.582(2)Å, β=a^c=130.8(0)° (C2/c); a₁=8.085(1)Å, b₁=b, c₁=c, β₁=a₁^c₁=94.3(9)° (I2/c)
Density	7.11 g/cm³
Specific heat	363 J/kg×K
Optical indicatrix frame	biaxial; N_p=b, c^N_g=19.3°, a^N_m=60.1° (C2/c); N_p=b₁, c₁^N_g=19.3°, a₁^N_m=14.9° (I2/c)
Refractive indices	n_p=2.0109, n_m=2.0414, n_g=2.0950 at 633 nm; n_p=1.9818, n_m=2.0101, n_g=2.0609 at 1064 nm
Optical axes position	N_g±42.6° (N_p-N_g plane) at 633 nm
Thermal conductivity	2.5 (N_p), 3.0 (N_m), 3.5 (N_g) [W/mK]
Linear thermal expansion coefficients	α'₁₁=7.6, α'₂₂=1.7, α'₃₃=20.6, α_vol=29.9 [10^-6 K^-1]; α_m=11.3, α_g=16.9 [10^-6 K^-1]
Principal frame of the thermal expansion tensor	X'₂=b(N_p), X'₃^N_g = X'₁^N_m=32.1°
Thermo-optic coefficients	dn_p/dT=-14.4, dn_m/dT=-9.7, dn_g/dT=-15.7 [10^-6 K^-1] at 633 nm; dn_p/dT=-15.7, dn_m/dT=-11.8, dn_g/dT=-17.3 [10^-6 K^-1] at 1064 nm
Strongest phonon modes	901 cm^-1 (E \|\| N_m), 768 cm^-1 (E \|\| N_g)
Nonlinear refractive index	n₂~25×10^-16 cm²/W (E \|\| N_m), ~15×10^-16 cm²/W (E \|\| N_p)
Raman shift	901 cm^-1 (p[mm]p), 768 cm^-1 (p[gg]p)
Raman gain, @1064 nm	3.3 cm/GW (901 cm^-1), 4.4 cm/GW (768 cm^-1)

Specifications for the KGW Raman elements

Material :                                 KGd(WO₄)₂Dimension tolerances:             ±0,05 mm
Surface quality:                       10/5 S/D
Surface flatness:                      l/10 @632.8nm
Perpendicularity:                     ±5 arcmin
Parallelism:                              ±5 arcsec
Chamfers:                                <0.1 mm @ 45°
Orientation:                             b-cut or Ng-cut

Solid-state Raman Shifter

The Solid State Raman Shifter LZ series uses innovative technology Ba(NO3)2 (shift 1047 cm-1) and KGdWO4 (shift 767.3 and 901.5 cm-1) crystals. The crystals’ unique properties allow their application for Raman frequency conversion ranging from VIS to IR. The nonlinear crystal placed in the optimized cavity ensures high conversion efficiency of the the pump radiation to the 1st, 2nd or 3rd order Stokes, alongside with low generation thresholds. Upon your order mirrors can be installed into the LZ221 Shifter for obtaining definite Stokes, as well as for receiving the multi-line output (generating several components simultaneously) with the total conversion efficiency more than 50%. The design of this device minimizes the needs for user adjustments and allows to easily replace cavity mirrors while re-aligning the Raman Shifter from one wavelength to another.
KGW Raman crystals

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