Advances in vanadate laser crystals at a lasing wavelength of 1 micrometer

Sapphire, garnet and vanadate crystals are the most prominent optical materials, and vanadates play important roles in optics, especially in lasers and nonlinear optics. Neodymium-doped yttrium vanadate (Nd:YVO4) is representative and available commercially. Based on Nd:YVO4, several vanadate crystals are being developed with the goal of fulfilling the need for differential applications and improvement of certain operational aspects, such as with pulsed lasers or high-power continuous-wave lasers. In recent years, some important effects, including energy enhancement, bistability of output performance, self-Raman frequency shifting, etc., and some novel applications, such as quantum optics, pulsed lasers modulated by the two-dimensional crystals, etc., have been discovered with vanadates as gain materials. In this paper, the preparation, characterization and laser applications of vanadate laser crystals at the lasing wavelength of 1 micrometer, including YVO4, GdVO4, LuVO4, GdxY1-xVO4 and LuxGd1-xVO4 (0 < x < 1) doped with Nd3+ and ytterbium (Yb3+) are systematically reviewed by highlighting the most recent research progress. Their specific properties are presented, generation mechanisms of novel physical effects are discussed, new applications are given and possible future applications proposed by focusing on some potential strengths.