Ultrahigh resolution OCT imaging with a two-dimensional MEMS scanning endoscope Aaron D. Aguirre, Paul R. Herz, Yu Chen, James G. Fujimoto Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics Massachusetts Institute of Technology, Cambridge, MA 02139, USA Wibool Piyawattanametha, Li Fan, ShuTing Hsu, Makoto Fujino, Ming C. Wu Department of Electrical Engineering, Integrated Photonics Laboratory University of California Los Angles, Los Angeles, CA 90095, USA Daniel Kopf High Q Laser Production GmbH A-6845 Hohenems, Austria ABSTRACT This paper reports preliminary results from the development and application of a two-dimensional MEMS endoscopic scanner for OCT imaging. A 1 mm diameter mirror provides high aperture over large scan angle and can scan at rates of hundreds of Hz in both axes. The mirror is integrated with focusing optics and a fiber-optic collimator into a package of ~5 mm diameter. Using a broadband femtosecond laser light source, ultrahigh axial image resolution of < 5 um in tissue is achieved at 1.06 um center wavelength. Ultrahigh resolution cross-sectional and three-dimensional OCT imaging is demonstrated with the endoscope with ~12 um transverse resolution and < 5 um axial resolution. Keywords: optical coherence tomography, endoscopy, MEMS 1. INTRODUCTION Optical coherence tomography (OCT) is a promising technique for high-resolution in situ imaging of biological tissues. Development of scanning fiber-optic catheters has enabled in vivo endoscopic OCT imaging 1, 2 , and results to date have shown the ability to distinguish tissue architectural layers and to differentiate normal from certain pathologic conditions within the human gastrointestinal tract 3-7 . A need for further development of compact, robust scanning devices for endoscopic applications has led to the development of micro-electromechanical systems (MEMS) scanning mirrors for confocal microscopy and for optical coherence tomography 8-14 . MEMS-based catheters with distal beam scanning can image with higher speed, precision, and repeatability than conventional linear scanning catheters in which the entire catheter is mechanically translated with respect to the tissue. These advantages will enable three dimensional endoscopic OCT imaging, which promises to enhance visualization of mucosal architecture and glandular morphology in the upper and lower gastrointestinal tracts. However, to date, demonstrations of integrated MEMS scanning OCT endoscopes have been limited to single-axis scanning. A two-dimensional MEMS scanning endoscope has been developed for OCT imaging. The MEMS scanning mirror is capable of both DC and resonant operation and can produce arbitrary beam scan patterns, enabling both cross-sectional and three-dimensional imaging. The integrated endoscope produces a transverse spot Advanced Biomedical and Clinical Diagnostic Systems III, edited by Tuan Vo-Dinh, Warren S. Grundfest, David A. Benaron, Gerald E. Cohn, Proc. of SPIE Vol. 5692 (SPIE, Bellingham, WA, 2005) · 1605-7422/05/$15 · doi: 10.1117/12.593143 277