Signal/noise ratio of orbital angular momentum modes for a partially coherent modified Bessel-correlated beam in a biological tissue.

The random fluctuation of the refractive index is an important factor that affects the light transmission in a biological tissue. Here we have derived an expression of signal/noise ratio or equivalent intensity of the orbital angular momentum (OAM) mode for the partially coherent modified Bessel-correlated beam in a turbulent biological tissue. Effects of specific parameters of the biological tissue on it have been studied, such as the outer scale of the tissue index inhomogeneities, the fractal dimension of the particle size distribution, temperature fluctuation strength, and the cutoff correlation length. We argue that selecting a small quantum number of OAM modes is an effective means to improve signal transmission quality. We can adjust the propagation distance, the wavelength of the light source, and the diameter of the receiving aperture to obtain the optimum signal detection results. Also, nondiffracting vortex light can increase the communication channel capacity. Our findings will provide an important theoretical basis for the design and research of medical devices.