Miniature variable optical delay using silicon micromachined scanning mirrors

Summary form only given.Optical coherence tomography (OCT) is a cross-sectional optical technique for high-resolution clinical imaging of microstructure in biological systems. OCT performs spatially localized imaging by combining coherent signal acquisition and joint time frequency analysis of wide-band near IR radiation in a white light interferometer. The technique requires a rapid (/spl sim/1-2 kHz) scanning optical delay (RSOD) in order to construct images at 4-8 Hz. Quasi-real time OCT imaging with a delay line of /spl sim/3 mm/sup 2/ has been demonstrated using scanners based on technology originally developed for femtosecond optical pulse diagnostics. We report the development of compact RSOD scanners that use, for the first time, silicon micromachined scanning mirrors. Use of a micromirror allows for high speed and low mechanical vibration. We investigate the design trades-off of a RSOD optimized for the stringent requirements of OCT, namely, large optical bandwidth and long linearly scanned delay range.