Abstract: Specific acoustic impedance of transparent liquid, sound transmitting distance of laser induced sound and laser beam waist radius are analyzed. It shows that the peak pressure, dominant frequency and energy of laser induced sound increase as specific acoustic impedance increases. The dominant frequency quickly drops in a short distance and then becomes a constant at a larger distance. Under the condition of optical breakdown, a high ratio of laser to sound energy conversion can be obtained with a large laser beam waist radius.

Key words: transparent liquid, laser induced sound, specific acoustic impedance, transmitting distance, beam waist radius