Research status and analysis of fifth-harmonic-generation for ~1μm laser

All-solid-state (ASS) ultraviolet (UV) laser is an organic combination of ASS laser technique and nonlinear frequency conversion technique. By using different kinds of nonlinear optical crystals and optimizing the system structure, the conversion efficiency and output power of fifth-harmonic-generation (5HG) of ASS lasers has been constantly updated. And the expected UV laser with high beam quality and stability was obtained through reasonable system design. In this paper, the research status of 5HG for ~1 μm near-infrared ASS lasers were briefly reviewed, different approaches for producing 5HG were compared, and the advantages and disadvantages of the corresponding approaches are analyzed.