Fig. 1.

Handheld probe used for optical palpation. (a) Photograph of the probe, with overlaid illustration of the six degrees of freedom. The probe body has dimensions 158 × 39 × 107 mm (L × W × H). (b) Schematic layout of the optical path in the handheld probe. SLD, superluminescent diode. PC, polarization controller. FC, fiber coupler. BD, beam dump. S, spectrometer. MEMS, microelectromechanical mirror system. BS, beam splitter. CCD, charge-coupled device. PA, piezoelectric actuator. IW, glass imaging window. OL, objective lens.