Two-photon excitation fluorescence(TPEF) and second-harmonic generation(SHG) are detected through multiphoton microscopy(MPM).The major signals have the potential to monitor the process of tissue changes.TPEF and SHG are used to monitor the skin photo-thermal response to irradiation with intense pulsed light sources(λis in the range of 560-1200 nm) and trace the process of skin remodeling in vivo at different time intervals.TPEF intensity is nearly unchanged at different time intervals after irradiation, whereas SHG intensity changes considerably.The results reveal the photo-thermal effect of nonablative light sources and the process of collagen remodeling at the sub-micron level.
A method based on morphological granulometric analysis for the speckle image is presented to estimate the scattering coefficient of the scattering media. It is experimentally demonstrated that the average granulometric size, derived from the successive opening operations, is approximately in inverse proportion to the scattering coefficient of the sample in a broad illumination. Furthermore, a theoretical model based on the spatial correlation function of the back scattered intensity for the experimental phenomenon is reported. The analysis demonstrates that the explicit theoretical relationship between average granulometric size of speckle and scattering coefficient is established, and the theoretical prediction is consistent with the experimental result.
We present a method for the noninvasive measurement of blood glucose levels, which are determined by the ultrasound-modulated optical technique. The method is based on the optical scattering coefficient. A sensitivity analysis of the ultrasound-modulated light signals in a scattering medium is conducted. Glucose concentrations in intralipid and hemoglobin solutions are measured using the modulation depth of ultrasound-modulated scattered light. The effects of incident light intensity and sample temperature on the ultrasound-modulated signals are also estimated. Preliminary experimental results suggest that the proposed method is a promising technique for noninvasive blood glucose measurement.
