GaSe Crystal
WaveQuanta

GaSe (Gallium Selenide) Nonlinear Crystal for Mid-IR SHG and THz, 0.62–20 µm

WQ-NLC-GASE
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Lasers & Sources Mirrors Nonlinear Crystals Optomechanics
RoHS REACH

Gallium selenide (GaSe) is a layered nonlinear crystal with a d22 coefficient of 54 pm/V and a transparency range of 0.62–20 µm. It is used for frequency doubling of mid-IR lasers such as CO2, CO and DF lasers, for up-conversion of IR radiation into the visible, for optical parametric generation and for THz generation. Because GaSe cleaves along the (001) plane and cannot be cut at arbitrary phase-matching angles, WaveQuanta supplies it as thin mounted plates, from 0.1 mm to 3 mm thick.

Key Features

  • Transparency range 0.62–20 µm
  • Nonlinear coefficient d22 = 54 pm/V
  • Optical damage threshold 30 MW/cm² at 1.064 µm (10 ns) and 28 MW/cm² at 9.3 µm (150 ns)
  • Up to 9% conversion efficiency reported for CO2 laser SHG
  • THz generation in the 0.1–4 THz range
  • Soft, layered crystal (Mohs hardness 2) that cleaves along the (001) plane
  • Plates are thinned layer by layer from a thicker blank; 0.2 mm is the usual minimum thickness, and 0.1 mm plates can be made without a flatness guarantee

Typical Applications

  • Second-harmonic generation of CO2, CO and chemical DF (λ = 2.36 µm) lasers
  • Up-conversion of CO and CO2 laser radiation into the visible range
  • Mid-IR pulse generation by difference-frequency mixing of Nd lasers with IR dye or F-centre lasers
  • Optical parametric generation within 3.5–18 µm
  • THz (T-ray) generation, 0.1–4 THz

Standard Sizes

Size Cut / orientation Surface / coating Mount
Ø5 × 0.2 mm — — Mounted
Ø5 × 0.3 mm — — Mounted
Ø7 × 0.2 mm — — Mounted
Ø7 × 0.3 mm — — Mounted
Ø7 × 0.5 mm — — Mounted
Ø7 × 0.6 mm — — Mounted
Ø7 × 0.8 mm — — Mounted
Ø7 × 1 mm — — Mounted
Ø7 × 2 mm — — Mounted
Ø7 × 3 mm — — Mounted
Ø8 × 0.1 mm Z-cut — Mounted
Ø8 × 0.4 mm — — Mounted
Ø8 × 0.6 mm — — Mounted
Ø8 × 2 mm Z-cut — Mounted
8 × 1 mm — — Mounted

Availability of individual sizes changes; custom sizes, cut angles and coatings are available on request.

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Model: WQ-NLC-GASE · Custom sizes, orientations and coatings on request — contact WaveQuanta for a quote and lead time.

Chemical Formula GaSe
Point Group 6̄m2
Lattice Parameters a = 3.74 Å, c = 15.89 Å
Density 5.03 g/cm³
Mohs Hardness 2
Cleavage Plane (001)
Transparency Range 0.62–20 µm
Refractive Indices at 5.3 µm no = 2.7233, ne = 2.3966
Refractive Indices at 10.6 µm no = 2.6975, ne = 2.3745
Nonlinear Coefficient d22 = 54 pm/V
Walk-off Angle 4.1° at 5.3 µm
Optical Damage Threshold 30 MW/cm² (1.064 µm, 10 ns); 28 MW/cm² (9.3 µm, 150 ns); 0.5 MW/cm² (10.6 µm, CW)
CO2 Laser SHG Efficiency Up to 9%
THz Generation Range 0.1–4 THz
Typical Minimum Thickness 0.2 mm (0.1 mm on request, flatness not guaranteed)
Typical Mounting 10 × 10 mm plate in a 1-inch diameter holder, clear aperture Ø9–9.5 mm
Specification Sheet PDF — Download
No CAD drawings available for this product.
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