We have demonstrated a high-power ultraviolet (UV) femtosecond laser based on an all-fiber photonic crystal fiber (PCF) laser. By combining a short, large-mode-area (LMA), high-gain silica PCF with a large-core rod-type PCF, the B-integral accumulation of the system is reduced. This ultimately enabled the generation of UV laser output at a wavelength of 343 nm, with a repetition rate of 1 MHz, pulse duration of 309 fs, average power of 41 W, and harmonic conversion efficiency of 26%. The beam quality of the UV laser is near-diffraction-limited with M2 factors of Mx2=1.11, My2=1.12. This UV femtosecond laser source has promising applications in fields such as semiconductor wafer dicing and biomedical imaging.
Su et al. (Thu,) studied this question.