Influence of biological tissue and spatial correlation on spectral changes of Gaussian-Schell model vortex beam

Abstract

Based on the extended Huygens-Fresnel principle, the analytical expressions of the spectrum for Gaussian-Schell model vortex beam (GSMVB) propagating in biological tissues have been derived. The effects of the field point position, the species of the biological tissues, spatial correlation of beams on the relative spectral shift of GSMVB passing biological tissues have been investigated using the contour plots. It is shown that the spectral change is somewhat slow on the area near the z-axis, whereas the spectral redshift, blueshift and jump occur at far off-axis range. The stronger biological tissue turbulence can delay spectral jump, extend the space of observing the beam spectral jump, weaken the phenomenon of spectral jump on the propagation. Simultaneously, the results can well verify the scientificity and rationality of selecting the mouse as the experimental objects in biomedical research. The spatial coherence of beams can speed up the spectral change and slow the spectral jump down. Additionally, several physical explanations have been given to the above phenomena.