| 摘要 |
PURPOSE:To detect the data of the inside at an arbitrary depth position in a sample highly accurately without decreasing the resolutions of a photo-acoustic signal in the lateral direction and in the depth direction by specifying both transmitting wavelengths through the sample for light for exciting the sample and for light for detecting a photo-acoustic effect. CONSTITUTION:Light having a wavelength which transmits through a sample 42 is obtained from a light source 31. The light undergoes intensity modulation 32 with intended frequency. The intensity-modulated light is condensed on the sample or in the inside of the sample. The condensed light spot is scanned at the inside of the sample in the depth direction of the sample, and a photo-acoustic effect is generated in the sample. Light having a wavelength which transmits through the sample is obtained from a light source 43. The light is condensed at the same position as the light spot position and made to scan. Interference light based on the reflected light or the transmitted light at the light condensed spot is utilized, and the phase change due to the photo-acoustic effect is detected. The data on the surface and the inside of the sample are extracted 77 based on the detected signal. Thus, the internal data at the arbitrary depth position in the sample are stably detected without the decrease in resolutions of the photo-acoustic signal in the lateral direction and in the depth direction. |
