HIGH RESOLUTION MEASUREMENTS OF OPTICAL TOMOGRAPHY IN SCATTERING MEDIUM

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Optical coherence tomography based on an optical frequency reflectometry has been developed. The system has been applied to measurements of reflectivity behind chiken tissue. The main results are shown as followings.(1) The optical frequency of tunable laser source can be linearly scanned upto 10 THz during 2 seconds without a mode-hoppe effect.(2) The data processing system with a CCD camera can be time-sequentially stored to memories of 512 frames, and be Fourier-transformed every pixel-data.(3) The depth resolution of this system is 47 mum for five minutes of short analyzing time by using the fast Fourier transform method.(4) The optical system which is constructed of two-lens system is inserted in the Micherlson interferometer. By using this system and an optical heterodyne system, the strong diffuse light from the scattering media was rejected to 10^<-9> of incident light intensity.(5) The system can measure three-dimensionally the reflectivity distribution inside strong scattering media from the surface to the depth of a few millimeters.(6) The reflectivity behind a chiken tissue was measured with measuring time of 2 seconds. From the results, the present system is available to three-dimensional reflectivity distribution measurements.