Enhancement of all-optical photoacoustic detection sensitivity via elliptical reflector

All-optical photoacoustic detection has poor inspection quality when it is used on rough surfaces due to strong light scattering. We report on the use of an elliptical reflector to improve the sensitivity of all-optical photoacoustic inspection on rough surface samples. By employing the bi-focal property of the elliptical reflector, the amplitude of the photoacoustic signal can be increased by 3 times. It also greatly improves the imaging quality of photoacoustic inspection of rough surface samples. This technique has the potential to extend the applications of all-optical photoacoustic detection in industrial applications, where rough surface samples are common.