Photoacoustic detection of weak absorption in lithium niobate

This paper presents a different approach: pulsed-laser photoacoustic (PA) spectroscopy with piezoelectric (PZT) sensors is used to determine the absorption through the amount of the energy deposited in the sample. This results in a simple experimental setup. Here, a frequency doubled Nd:YAG laser (λ = 532 nm) was used. The setup allows the variation of pulse energy (10 μJ to 100 mJ), pulse duration (5 to 20 ns) and beam diameter (0.1 mm to 4 mm) for a systematic investigation of the PA signal generated in the LiNbO₃ crystals.