Linearly-polarized pulsed Nd-doped fiber MOPA at 905 nm and frequency conversion to deep-UV at 226 nm

Abstract

We present the first frequency-quadrupled linearly-polarized Q-switched neodymium-doped fiber laser generating > 500 mW average power at 226 nm. For this purpose, an amplified Q-switched oscillator using novel large-mode-area (LMA) fibers and generating up to 24 W average power (15 kW peak power) at 905 nm was developed. Two nonlinear frequency conversion stages using a LBO crystal for SHG and a BBO crystal for FHG generate respectively up to 4.9 W average power in the deep blue at 452 nm and a maximum of 510 mW average power in the deep ultra-violet (DUV) at 226 nm. Performance limitations and further improvements are discussed.

High power continuous laser at 461 nm based on a compact and high-efficiency frequency-doubling linear cavity

“…The drawback represented by the poor mode quality is significantly mitigated by exploiting the two main lobes of the output beam. A higher output power and more integrated setup could exploit a fully-fibered amplifier [23] and large mode area fibers [30] for the fundamental frequency.…”

Generation of 12th order harmonic mode-locking in a Nd-doped single-mode all-fiber laser operating at 0.9 µm

“…Secondly, a frequencydoubling 0.9 μm laser can generate a pure blue laser of ∼460 nm, which has great application value in the fields of material processing, optical information storage, and display technology [18] . Further, 0.9 μm mode-locked fiber lasers can be used to generate deep ultraviolet (DUV) at 226 nm after frequency quadrupling [19] . DUV high-energy pulsed lasers with wavelengths less than 250 nm have important values in dermatology, material processing, and laser-induced spectroscopy.…”