High-power narrowband DUV laser source by frequency mixing in CLBO

We describe an all solid-state, high power, deep-UV (DUV) source based on sum-frequency mixing (SFM) of two single- frequency laser outputs. The system consists of a CW diode- pumped, Q-switched Nd:YLF laser operating at 1047 nm, a Ti:sapphire laser at 785-nm, and cascading SFM stages. Both laser sources are configured with an injection-seeded oscillator followed by amplifier to produce high power, single-frequency, TEM₀₀ outputs. The third harmonic of Nd:YLF MOPA is mixed with the output from Ti-sapphire MOPA to generate the first UV, which is used for the second mixing with the residual fundamental output to generate the DUV radiation. CLBO crystal is employed for each SFM process. The system produced UV pulses at 241.6 nm with 3.4 W, and also DUV at 196.3 nm with 1.5 W of average powers at a 5-kHz pulse- repetition rate. The linewidth of the DUV output was measured to be less than 0.05 pm.