Laser-induced point source for scale model measurements

The laser-induced air breakdown is produced by focusing a high energy pulsed laser beam which heats rapidly the air at the focusing point. This produces a tiny explosion which generates a sonic impulse. The sonic pulse is repeatable, omnidirectional and broadband. Furthermore, the laser-induced air breakdown can be projected inside an enclosed space through a window of transparent material thus providing a massless source. The laser-induced air breakdown concentrates most of its sonic energy between 1 kHz and 100 kHz which suggests that it can be used for scale model measurements. The impulse response of an enclosed space made of glass, that represents a rectangular room, was measured using laser-induced air breakdown and compared to a computer simulation. The measured impulse response matched the simulated response of the scale room which confirms that laser-induced breakdown can be used as point source in scale model acoustic work.