Key Features
- Wide transmission range (0.62-20 μm)
- High nonlinear coefficient (d₃₆ = 54 pm/V)
- High damage threshold
- Broad phase matching capabilities
- Exceptional optical homogeneity
Description
Gallium Selenide (GaSe) is a layered, hexagonal crystal with a space group of 6̅m2, possessing a bandgap energy of 2.2 eV at 300K. GaSe crystals are known for their high nonlinear coefficient, wide transmission range, and high damage threshold, making them ideal for mid-infrared (IR) nonlinear optical applications. The material’s properties make it suitable for THz generation and detection, offering broad frequency tunability up to 41 THz.
Physical Properties
- Crystal Structure: Hexagonal
- Lattice Constants: a = 3.74 Å, c = 15.89 Å
- Density: 5.03 g/cm³
- Mohs Hardness: ≈ 2
- Bandgap Energy: 2.2 eV at 300K
Optical Properties
- Transmission Range: 0.62-20 μm
- Refractive Indices:
- nₓ = 2.7233 @ 5.3 μm
- nᵧ = 2.3966 @ 10.6 μm
- n_z = 2.3745 @ 16.0 μm
- Nonlinear Coefficients: d₃₆ = 54 pm/V
- Absorption Coefficient: < 0.005 cm⁻¹ @ 10.6 μm
Standard Specifications
- Optical Homogeneity: Δn ≈ 10⁻⁶/cm
- Flatness: λ/8 @ 633 nm
- Surface Quality: 10-5 scratch & dig (MIL-PRF-13830B)
- Parallelism: < 20 arcsec
- Perpendicularity: < 5 arcmin
- Angle Tolerance: < 30 arcmin
- Clear Aperture: > 90% of full aperture
- Damage Threshold:
- 28 MW/cm² @ 5.3 μm, 150 ns
- 0.5 MW/cm² @ 10.6 μm, continuous wave
- 30 MW/cm² @ 1.064 μm, 10 ns
Other Properties
- Thermal Conductivity:
- 0.15 W/mK (parallel to layers)
- 0.04 W/mK (perpendicular to layers)
- Thermal Expansion Coefficients:
- αₐ = 4.8 × 10⁻⁶/K
- α_c = 1.2 × 10⁻⁶/K
Applications
- Difference Frequency Generation (DFG): Used to produce mid-infrared and THz radiation.
- CO₂ Laser Frequency Doubling: Enhances the frequency of CO₂ lasers.
- Terahertz Generation and Detection: Ideal for applications requiring THz radiation.
- Nonlinear Optical Mixing: Suitable for various nonlinear optical processes, including parametric oscillation and amplification.
Processing and Handling
GaSe crystals require careful handling due to their relatively low hardness and layered structure. They should be stored in a controlled environment to prevent contamination and mechanical damage. Standard AR/HR coatings can be applied to enhance performance and protect the crystal surface.
Why Choose Shape Optics
Shape Optics provides high-quality GaSe crystals with precise control over physical and optical properties. Our crystals undergo rigorous quality control to ensure they meet the highest industry standards.
Shape Optics Strength and Capabilities
- High-Quality Materials: We use the finest raw materials and advanced manufacturing processes.
- Custom Solutions: Tailored solutions to meet specific application requirements.
- Global Reach: Exporting high-quality crystals to clients worldwide.
- Expert Support: Comprehensive technical support from our experienced team.
By choosing Shape Optics, you are assured of premium products backed by exceptional service and support.
