Correlation-induced spectral changes in tissues
We report experimental evidence of correlation-induced spectral changes in biological tissues. The overall spectral shift is to the red and the mean wavelength of the original spectrum can be as high as 10% longer. These results indicate that the spectral changes due to elastic scattering are significant and likely to hinder all spectroscopic measurements at angle based on the inelastic (i.e., emission and absorption) interaction between light and tissues. Thus, simultaneous morphology and spectral measurements are required for accurate measurements spectroscopic information. This spatial correlation induced spectral change can be seen as an effect of diffraction, that redistributes energy rather than emitting new light.
Left: Spectral Changes against scattering angles simulated with Gaussian spectrum on a tissue sample. Right：Relative shift on mean spectrum is calculated for Gaussian, HbO2 and Hb absorption spectrum.
