Multifunctional laser crystal

摘要

Self-frequency converted lasers provide a valuable tool for efficient frequency conversion. With this technique it is not only possible to access particular spectral regions out of reach for other solid state lasers but also to translate operative characteristics like portability, miniaturisation of well established laser systems to new spectral regions. The case of green diode-pumped microchip self-frequency doubled lasers based on Nd{sup}(3+) ions embedded in nonlinear host crystals is a well-known example of all-solid-state lasers accessing a spectral range formerly dominated by ion gas lasers. Early self-frequency lasers based on birefringent phase matching although useful, have some fundamental limitations. With the use of domain engineered ferroelectric crystals like lithium niobate, it is possible to overcome some of the limitations. For instance, it is possible to improve thermal tolerance avoiding stringent temperature control, or to provide simultaneous multiple or tuneable self-frequency conversion [1].