A method and apparatus are described for detecting the presence of explosives. The invention utilizes Laser Induced Acoustics (LIA), wherein an area of a substrate surface is irradiated, via deep UV pulsed laser, with laser pulses to generate a detectable audible signal. The invention also provides substantial improvements in the eye-safety of otherwise potentially harmful laser beams. Thus, the invention is particularly well-suited to use in public venues where detection of explosives or improved laser safety may be required.