Alleviation of thermally induced phase mismatch in CsLiB6O10 crystal by means of temperature-profile compensation

A new mechanism was found to alleviate the thermally induced phase mismatch of nonlinear optical crystals. By cooling CsLiB>(6)O(10) at an elevated crystal temperature with gas, we improved laser conversion efficiency from green (532 nm) to UV (266 nm) 2.3 times compared with that without cooling. In situ observation of the temperature profile on the output surface revealed that such cooling initiates a negative temperature profile that compensates for the positive profile generated from laser absorption. A 10.6-W UV output with excellent stability was generated. The optimum crystal length was substantially extended.