[20a-E313-1~10] 3.4 Biomedical optics

△ [20a-E313-1] Development of pump-probe spectroscopy using noise modulation for spectral photothermal microscopy

〇Hiromu Yamada¹, Keisuke Seto¹, Takayoshi Kobayashi², Eiji Tokunaga¹ (1.Tokyo Univ. Sci, 2.Univ. Electrocommun)

Keywords:photothermal microscopy, imasing, non-label

In order to obtain the excitation wavelength spectrum of the response of a sample in the pump-probe spectroscopy, a simultaneous multi-wavelength measurement has been realized in which pump light is modulated at different frequencies for each wavelength to discriminate excitation wavelengths. However, in photothermal microscopy, where the sample response is slow, spectral distortion occurs because phase delay in the response, which determines its gain, of the sample varies at different modulation frequency to identify excitation wavelength. Therefore, we have developed a spectroscopic method of modulating each wavelength component in white pump light with non-correlated noise to discriminate excitation wavelength. Since the modulation frequency band of the noise is the same for each wavelength, the gain unbalances in different excitation wavelengths is suppressed.