# Vol. 48, Issue 2, pp. 297-309

### Keywords

random electromagnetic vortex beam, biological tissue, the state of polarization

### Abstract

The changes in the on-axis polarization state of random electromagnetic Gaussian Schell-model vortex beams propagating in biological tissues have been studied. In different media propagation, the bigger C_{n}^{2} is, the earlier the appearance of the inflexion points in the on-axis degree of the polarization P(0, 0, z) is. As the propagation distance increases, the values of the on-axis orientation angle θ(0, 0, z) undergo several processes: at the beginning they are positive, then gradually increase to the maximum, jump to a negative value, finally tend to a fixed value. The bigger C_{n}^{2} corresponds to previous jumping position. In the entire propagation, the values of the on-axis ellipticity ε(0, 0, z) are larger than the initial one. There exists a phenomenon that the values of P(0, 0, z), θ(0, 0, z) and ε(0, 0, z) keep their extremes in a length of propagation distances for the far infrared beams. The maximum of P(0, 0, z) is the smallest and the jumping range of θ(0, 0, z) is the largest for the ultraviolet beams. Compared with σ_{yy} > σ_{xx}, the changes in magnitudes in P(0, 0, z) are more obvious when σ_{yy} < σ_{xx}, the changes in θ(0, 0, z) are just the reverse for σ_{yy} < σ_{xx}.