A 2.8-mm imaging probe based on a high-fill-factor MEMS mirror and wire-bonding-free packaging for endoscopic optical coherence tomography

This paper reports a miniature optical coherence tomography (OCT) probe and high-resolution 3-D OCT imaging results obtained with this side-view probe. The probe is only 2.8 mm in diameter, enabled by a unique high-fill-factor electrothermal MEMS mirror with hidden actuators and a novel wire-bonding-free packaging technique. The MEMS mirror has a large mirror aperture of 1 mm with a chip size of only 1.55 mm × 1.7 mm × 0.5 mm. The fabricated device achieves large 2-D scan optical angles up to 46° at only 4.8 V. The specific time-domain OCT system utilized is detailed, and the assembled side-view probe demonstrates multiple high-resolution 3-D OCT imaging results that demonstrate detailed images of a mouse ear and images detecting the presence of tumor cells, and the contrast with a normal tissue is qualitatively analyzed.