Real-time photodisplacement microscope for high-sensitivity simultaneous surface and subsurface inspection.

We have developed a new photodisplacement microscope system for practical use that achieves high-sensitivity simultaneous real-time imaging of surface and subsurface structures from a single space-frequency multiplexed interferogram. In this system a linear region of photothermal displacement is excited on the sample surface for subsurface imaging by a line-focused intensity-modulated laser beam. Surface information such as reflectivity and topography along with the displacement is detected with a charge-coupled device sensor-based parallel heterodyne interferometer.