摘要 |
A laser beam, which has been formed into the shape of a conical beam, is irradiated to a sample and is displaced with respect to the sample such that the laser beam may helically scan the sample. The laser beam having passed through the sample to the same direction as the direction, along which the laser beam impinging upon the sample propagates conically, is selected from the laser beam, which has scanned the sample and which has been radiated out of the sample, by using an image forming lens and a pinhole. A two-dimensional intensity distribution of the laser beam, which has passed through the sample and which has been selected, is detected. Three-dimensional information representing the form and/or structure of the sample is then obtained from the detected two-dimensional intensity distribution by using a computed tomography technique. Three-dimensional information of a sample containing a light scattering medium is thereby obtained accurately.
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