4:00 PM - 4:15 PM
△ [8p-Z19-11] Application of Syncrohous Filters to Accelerate Pseud-random Wavelength Multiplexing/demultiplexing Processing for Spectral Photothermal Microscopy
Keywords:photothermal spectroscopy, pump-probe spectroscopy, non-label
In photothermal microscopy, a thermal lens induced by the pump light absorption is detected by the probe light. We have developed a multiplexing technique for spectral photothermal microscopy, where the pump light wavelength is multiplexed with pseud-random sequences (M-sequences). A practical application requires the rejection of the direct current (DC) component to secure dynamic range and the time-integration in the correlation operation in the demultiplexing processing. Previously, we applied passive filters to meet the requirements, which is an obstacle against fast measurement. In this study, the DC component in the demultiplexing processing is canceled by a synchronous high-pass filter and adjustment of the amplitude ratio of the positive and negative elements in the M-sequences. The time-integration is operated in one-cycle of the M-sequence with a resettable integration circuit. With this circuity, measurement time is speeded up to the 2-cycle period of the M-sequence.