Nanosecond-Pulsed Frequency-Doubled Laser in Monoclinic Single-Crystalline KDP Microstructures

We demonstrate that nanosecond-pulsed second-harmonic (SH) power generation in monoclinic single-crystalline KDP microstructures for the first time by employing a Nd:YVO
₄
Q-switched laser. The experimental results show that the frequency doubling conversion efficiency is related to KDP microstructures' length and diameter. Using a monoclinic KDP microstructure with 0.95-mm length and 25 μm diameter, we generate 705 μW of nanosecond pulsed light at 532 nm for a fundamental power of 908 mW at a conversion efficiency of 8.55× 10
^-4
W
^-1
. By studying the polarization characteristics of SH power generation, type-I phase matching is found in the monoclinic single-crystalline KDP microstructures.