High-energy Alexandrite picosecond laser using the self-injection technique

Abstract

High-energy ultrashort pulse lasers have been developed in a variety of applications such as medical treatment, defense, semiconductor and manufacturing. In terms of aesthetic dermatology, Alexandrite (Cr 3+ :BeAl2O4) lasers have an attractive and useful wavelength band (700~800nm). Therefore, alexandrite lasers with shorter pulses and higher energy are required in the medical device market. Since alexandrite medium has a low energy gain at room temperature, it is not easy to make a flash-pumped picosecond alexandrite laser that produces sufficiently high output energy. To generate high-power picosecond laser pulses, we used self-injection and ultra short pulse generation techniques including Q-switching and cavity dumping. We have developed picosecond 755 nm alexandrite laser which can be operated at pulse width in the range from 600 to 2000 ps. A maximum average output energy of 400mJ was achieved in the picosecond regime.