Development of highly repetitive phosphate glass lasers

Abstract

High repetition rate operation of glass lasers up to 30 Hz has been successfully achieved for the first time by developing and using new kinds of phosphate glass. The key point of the success is to make the variation of optical path measured at any distance from the center of the glass rod nearly equal to zero by canceling out the effect of the temperature change of the index of refraction with that of the thermal expansion. This provides a new criterion on the glass design. The glass laser will not suffer any more from the disadvantage of the low thermal conductivity of the material, and its quality may become comparable with that of the YAG laser. The application of these kinds of glass into high‐power lasers has enabled us to construct a high repetition rate high‐power laser system (1 GW, 10 Hz), which will provide new applications to basic science and engineering.