GaSe Terahertz Crystals

Gallium selenide (GaSe) crystals for broadband THz generation with a bandwidth of up to 41 THz and for broadband mid-infrared generation. GaSe is a negative uniaxial layered semiconductor with a high damage threshold, a large nonlinear coefficient (54 pm/V) and low absorption; crystal thickness is chosen for frequency-selective THz generation and detection. Because GaSe cleaves only along the (001) plane and is soft and fragile, crystals are Z-cut cleaved and supplied in holders of 25.4 to 70 mm diameter, with thicknesses from 0.01 mm upward.