Development of a tunable, narrow, and ultraviolet Ce:LiCAF crystal multipass laser amplifier for environmental application

In this paper, the authors present results on the development of both an oscillator and a 4-pass amplifier of ultraviolet and narrow linewidth pulses using a Ce:LiCAF crystal. By using a grating at one end of the laser cavity, the output laser wavelength of the laser can be tuned from 285 nm to 296 nm with a maximum output power of 8 mW at 288.5 nm. Moreover, amplification in a 4-pass amplifier of the Ce:LiCAF laser was investigated theoretically and experimentally. From the results, 49.0 mW amplified pulses can be obtained using a 4-pass amplifier with 7.0 mW power and 3.6 ns pulse duration at 288.5 nm injection, corresponding to an amplifier gain of 7. Furthermore, the angular scattering intensity of some common single-particle aerosols such as black carbon, brown carbon, and polluted water has been studied using the Ce:LiCAF laser. This result can serve as the basis for the multipass laser amplifier’s environmental application, particularly in identifying atmospheric particles.