Potassium gadolinium tungstate (KGd(WO₄)₂, KGW) crystals are monoclinic crystals known for their excellent mechanical and optical properties. With a broad transparency range (0.3 µm to 5 µm) and significant thermal conductivity values, KGW are a reliable choice for demanding applications in Raman lasers and nonlinear optics. They offer two prominent Raman modes at 768 cm⁻¹ and 901 cm⁻¹, making them particularly effective for picosecond laser applications. KGW’s mechanical stability and ease of fabrication, combined with their strong polarization-dependent Raman effects, provide users with a versatile tool for advanced photonic applications.
KGW are extensively utilized in advanced photonic systems. Key application examples include:
These features make KGW an ideal crystal for Raman shifters, nonlinear optics, and other cutting-edge photonic applications.
| Property | Value |
|---|---|
| Chemical Formula | KGd(WO₄)₂ |
| Crystal Structure | Monoclinic, Space Group C2/c |
| Lattice Parameters | a = 10.6542(4) Å, b = 10.374(6) Å, c = 7.5820(2) Å |
| Density | 7.27 g/cm³ |
| Mohs Hardness | 4-5 |
| Transparency Range | 0.3 µm – 5 µm |
| Thermal Conductivity (kₐ) | 2.6 W·m⁻¹·K⁻¹ |
| Thermal Conductivity (kᵦ) | 3.8 W·m⁻¹·K⁻¹ |
| Thermal Conductivity (k𝚌) | 3.4 W·m⁻¹·K⁻¹ |
| dn/dT (Temp Coefficient) | dn/dTₐ = -15.7 × 10⁻⁶ K⁻¹ |
| dn/dTᵦ = -18.3 × 10⁻⁶ K⁻¹ | |
| dn/dT𝚌 = -17.3 × 10⁻⁶ K⁻¹ |
| Property | Value |
|---|---|
| Refractive Indices (nₐ) | nₐ = 1.982 |
| nᵦ = 2.096 | |
| n𝚌 = 2.061 | |
| Raman Frequency Shifts | 901 cm⁻¹, 768 cm⁻¹ |
| Raman Linewidth | 5.4 cm⁻¹ (polarization pump lp mlp) |
| 6.4 cm⁻¹ (polarization pump gp lgp) | |
| Raman Gain | 11 cm/GW@532 nm |
| 3 cm/GW@1064 nm | |
| Dephasing Time | 2 ps |
| Specification | Value |
|---|---|
| Orientation | b-cut |
| Clear Aperture | >90% |
| Face Dimension Tolerance | ±0.0/-0.1 mm |
| Length Tolerance | ±0.1 mm |
| Parallelism Error | <20 arcsec |
| Perpendicularity Error | <10 arcmin |
| Surface Quality (Scratch/Dig) | 10-5 S-D |
| Surface Flatness | <λ/8 @ 632.8 nm |
| Coatings | ARR@450-800 nm; 500-650 nm |
| Mount | Unmounted |
KGW crystals exhibit high transmission in the range of 0.3 µm to 5 µm, allowing effective Raman shifting and nonlinear optical processes. The two Raman modes at 768 cm⁻¹ and 901 cm⁻¹ are distinctly visible in Raman scattering experiments, confirming the crystal’s excellent optical performance.
| Face Dimensions | Length | Coatings | Price (USD) |
|---|---|---|---|
| 5 x 5 mm | 15 mm | Uncoated | 440 |
| 5 x 5 mm | 30 mm | ARR@450-800 nm | 600 |
| 5 x 5 mm | 45 mm | Uncoated | 610 |
| 5 x 5 mm | 50 mm | ARR@450-800 nm | 900 |
| 8 x 8 mm | 50 mm | ARR@450-800 nm | 1120 |
