[OPTICAL REVIEW Vol. 7, No. 5 (2000) 432-435]
Optical Computed Tomography Based on Extraction of Quasi-Straight-forward Propagating Photons Using Sum-Frequency Generation Technique
Kenji WADA,1 Yasuhiko SATOMURA,1 Hiroshi KAMIE,1 Takafumi KIUCHI,1 Hiromichi HORINAKA,1 Yoshio CHO,2 Tokuo UMEDA3 and Kenji NAKAMURA4
1Department of Physics and Electronics, Graduate School of Engineering, Osaka Prefecture University, Gakuen-cho, 1-1, Sakai, Osaka, 599-8531 Japan, 2Okayama Research Lab, Oyokoden Applied Photonics Lab Co., Ltd., 3205, Tomiyoshi, Okayama, Okayama, 701-1133 Japan, 3School of Allied Health Sciences, KITASATO University, 1-15-1, Kitasato, Sagamihara, Kanagawa, 228-8555 Japan, 4Tsukuba Technology Center, Shimadzu Co., Ltd., 3-17-1, Azuma, Tsukuba, Ibaraki, 305-0031 Japan.
(Received May 19, 2000 ; Accepted June 30, 2000)
Aiming at the realization of optical computed tomography (optical CT), a compact system comprised of two cw-lasers and a detector was proposed for the extraction of quasi-straightforward propagating photons from scattered light transmitting through a scattering medium. The extraction ability of the system based on the sum-frequency generation technique was investigated using a standard scattering medium of Intralipid-10% aqueous solution and was found to be 78 dB in dynamic range. The optical CT image of absorbers placed in the scattering medium was successfully obtained with high contrast using the proposed system.
Key words : optical computed tomography, scattering, quasi-straightforward propagating photons, sum-frequency generation, coherence detection