Noninvasive monitoring of blood glucose is the current international academic research focus. Near-infrared (NIR) spectroscopy is the most prospective method of the present study, however, with the flaw of insufficient specificity to glucose. Tissue polarimetry has recently received considerable attention due to its specificity to glucose. Thus the glucose predicting accuracy would be improved by combining spectral intensity and polarization characteristics. However the backscattering spectral polarization characteristics of turbid media have not been reported within the wavelength range from visible to near-infrared light. In this paper, we simulated the backscattering spectral Mueller matrix of turbid medium by vector Monte Carlo. And the polarization characteristics, which are linear/circular degree of polarization (DOP) and linear/circular diattenuation, can be extracted from the simulated Mueller matrix by polar decomposition. Circular diattenuation is not discussed because it remains almost zero on the backscattering plane. While reduced scattering coefficient increases linearly with increasing wavelength, the spectral curves show distinct wavelength dependencies. Interestingly, the wavelength dependencies at center position are different from those at off-center position for linear/circular DOP and linear diattenuation. As expected, it is shown that both linear DOP and linear diattenuation increase with the increasing wavelength. However it is not the case for linear DOP in the central area around the incident point. In this area linear DOP decays approximately exponentially with increasing wavelength. As for circular DOP, it varies with wavelength non-monotonically. These results should be meaningful when spectral polarization characteristics are used to combine with spectral intensity to extract glucose concentration by chemometrics.
In this paper, polarization property of RBCs was discussed by polar decomposition. Experimental results were compared
with a three-dimensional Monte Carlo simulation for the erythrocyte suspensions with the same concentration. And there
is a good agreement for both experimental and simulative results. Furthermore, Mueller matrices were measured for
erythrocyte suspensions with different concentration under 10%, in this condition light coherent phenomena can be
ignored. Using polar decomposition, the conclusion comes out that degree of polarization (DOP) and diattenuator for
erythrocyte suspensions decrease with increasing concentration. Because when suspension concentration increases,
scattering coefficient will be changed increasingly simultaneously and DOP and diattenuator decreases with added
scattering times. These results will be referred as useful information for noninvasive diagnosis of blood.
A new feature of relationship between macro-bending losses and bending length of mono-mode fibers is found experimentally: when bending radius is 4mm nearly no loss is detected on the condition that bending angle is less than 20 degrees. The similar phenomena happen when bending radius is 3mm or 2mm. The turning bending degree that bending losses will increase rapidly is called critical angle by us. The result will give us some new clues that how the bending losses change with bending length on earth. And some theoretical work should be done to explain the phenomenon.