Abstract:We presented an efficient 35.1 W all-solid-state 355 nm ultraviolet laser. The external cavity nonlinear frequency conversion was used while a 100-W level AO Q-switched Nd:YVO 4 MOPA laser was used as the infrared source. Type I noncritical phase-matching LBO and type II phase-matching LBO were used for frequency doubling and sum-frequency mixing respectively. About 100 W TEM 00 mode 1064 nm laser was obtained from the MOPA laser when the pulse repetition rate increased from 65 kHz to 100 kHz. The highest 35.1 W average power of 355 nm ultraviolet laser was obtained from the nonlinear frequency conversion at 70 kHz with the pulse duration of 15.7 ns and optical conversion efficiency of 35.8% (infrared to ultraviolet), corresponding to the pulse peak power and pulse energy of 32 kW and 0.5 mJ respectively. The average power of ultraviolet laser varied from 28.5 W to 34.9 W when the pulse repetition rate decreased from 100 kHz to 65 kHz. The detailed output performance varying with pulse repetition rate, and the power stability of the ultraviolet laser, were also investigated. The average output power for the IR ( ), green ( ), and UV ( ) laser varying with the PRF

We have measured an intense THz radiation produced by a sub-picosecond, relativistic electron bunch in a dielectric loaded waveguide. For efficient THz pulse extraction, the dielectric loaded waveguide end was cut at an angle. For an appropriate choice of angle cut, such antenna converts the TM 01 mode excited in the waveguide into a free-space fundamental Gauss-Hermite mode propagating at an angle with respect to the electron beam trajectory. Simulations show that more than 95% of energy can be extracted using such a simple approach. More than 40 oscillations of about 170 ps long 0.48 THz signal were explicitly measured with an interferometer and 10 lJ of energy per pulse, as determined with a calorimetric energy meter, were delivered outside the electron beamline to an area suitable for THz experiments.

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