A HIGH-SPEED CONFOCAL LASER ENDOMICROSCOPE USING AN ELECTROTHERMAL MEMS MIRROR ACTUATED IN LINEAR- NEAR RESONANT RASTER SCAN

Confocal laser endomicroscopy has profound impact in precision medicine, but is still facing challenges of ensuring high-speed in vivo imaging and guaranteeing safety. Electrothermal micromirrors typically have large linear angular scan range at low actuation voltage, allowing the safe laser scanning imaging. This paper reports a confocal endomicroscope using a two-axis electrothermal MEMS mirror actuated in near resonance to achieve a stable high-speed imaging. Fluorescent beads and micromachined patterns are used to test the probe performances. Experiments show that the lateral resolution is 4.15 mu m and the field of view is about 300x800 mu m(2). The imaging speed can be set from 1 fps to 20 fps with different pixel resolutions. In a linear-near resonant mode, the imaging frame rate of the probe is 20 times faster than that of a linear-linear mode at the same pixel numbers.