Manabu SATO¹, Akira MASUDA¹, Hitoshi OHOTAKI¹ and Naohiro TANNO^1,2

¹Yamagata University, Yonezawa City, Yamagata 992-8510, Japan
²Japan Science and Technology Corporation, JST Regional Joint Research Project of Yamagata Prefecture, 2-2-1 Matsuei, Yamagata 990-2473, Japan

(Received February 10, 2003; Accepted April 8, 2003)

An imaging interferometer with two long gradient-index (GRIN) lenses and a charge coupled device (CCD) sensor array is proposed and studied for application to an optical coherence tomography system that can observe the subsurface structure of internal organs through a small hole in the body. An image of lines 11 μm wide was obtained using the phase-shifting method and a test pattern as a sample. The lateral resolution obtained was 22 μm. The axial resolution was also measured and found to be 19.4 μm by measuring the coherence function. The dynamic range was about 60 dB, based on the RF spectrum of the beat signal. A sectional image of a 10-yen Japanese coin was measured as a rough surface sample.

Key words: optical coherence tomography, imaging interferometer, GRIN lens, phase-shift method