Fiber-optic confocal microscope with an electrothermally-actuated, large-tunable-range microlens scanner for depth scanning

We present a fiber-optic reflectance confocal microscope using a large-tunable-range MEMS microlens scanner for automatic axial scan. The tunable microlens is actuated by an electrothermal actuator that is capable of scanning up to 0.9 mm at less than 6.3 V. The lateral shift and tilt of the microlens are about 10 ¿m and 0.4°, respectively. 2-D cross-sectional reflectance confocal images of micro-particles in polymer and rat skin have been obtained with the lateral and axial resolutions of about 1.2 ¿m and 38 ¿m, respectively.