Doped GaSe crystals for laser frequency conversion

Abstract

Doping of gallium selenide (GaSe) is effective for controlling the physical properties that affect its frequency conversion efficiency. Despite its promising properties for nonlinear optical conversion, GaSe has not achieved the wide application that some other nonlinear optical materials enjoy. This is mainly due to the weak interlayer van der Waals bonding, which makes it difficult to grow and process large, single-crystals samples of high optical quality. Scientists in Russia and China review the growth of nonlinear GaSe crystals for laser frequency conversion. In particular, they assess recent progress in using doping to modify the physical properties of GaSe crystals. Doping confers many benefits, including raising the optical damage threshold, effectively eliminating two-photon absorption and enabling dispersion in the terahertz range to be controlled independently of that in the mid-infrared range.