Gallium Arsenide (GaAs)

Use GaAs for transmissive and reflective optics in applications where mechanical hardness, mechanical strength, and abrasion resistance are important.

Coherent produces GaAs with the characteristics required for optical applications by applying laser vacuum calorimetry and other techniques to screen out material with voids, inclusions, or other defects that cause inferior optical performance.

Gallium Arsenide (GaAs) Characteristics

Coherent supplies GaAs substrates of up to 100 mm diameter, and carefully monitors 10.6 µm absorptivity to ensure that thermal runaway and fracture do not occur.

GaAs Material Properties

Physical Properties

Young’s Modulus

83 GPa (12.04 x 106 psi)

Rupture Modulus

138 MPa (20,000 psi)

Knoop Hardness

750 kkg/mm²


5.37 g/cm³

Poisson’s Ratio


Thermal Properties

Thermal Conductivity @ 20° C

0.167 W/cm/°C

Specific Heat

0.469 J/g/°C

Linear Expansion Coefficient @ 20° C

6.8 x 10-6/°C

Optical Properties

Bulk Absorption @ 10.6 μm

<0.01 cm-1

Temperature Change of Refractive Index @ 10.6µm

149 x 10-6/°C