1 kHz 3.3 µm Nd:YAG KTiOAsO4 optical parametric oscillator system for laser ultrasound excitation of carbon-fiber-reinforced plastics

We present a new laser prototype for laser ultrasonics excitation. The fundamental wavelength of a Q-switched Nd:YAG laser with a repetition rate of 1 kHz is converted to 3.3 \textgreekmm with a KTiOAsO4 optical parametric oscillator. The achieved pulse energy at 3.3 \textgreekmm is 1.7 mJ, and the pulse duration at the fundamental wavelength of 1.06 \textgreekmm has been measured to be 21 ns. The ultrasonic excitation efficiency is about 3.5 times better compared to the application of state-of-the-art CO2 lasers