Effect of the turbulent biological tissues on the propagation properties of Coherent Laguerre-Gaussian beams

Ahmed Abdulrab Ali Ebrahim,Abdelmajid Belafhal

doi:10.1007/s11082-021-02838-7

Ahmed Abdulrab Ali Ebrahim, Abdelmajid Belafhal

Open Access

https://doi.org/10.1007/s11082-021-02838-7

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Abstract

In this paper, the effects of turbulent biological tissues (TBT) on the propagation properties of the coherent Laguerre-Gaussian (CLG) beams are studied. Based on the turbulence theory and using the power spectrum refractive-index model, the expression formulae of the average irradiance intensity and spreading properties of a CLG beam propagating in TBT are derived. The influence of propagation distance, beam orders, wavelengths and tissue turbulence parameters are then investigated numerically. It found that, the central dark zone of the circular/elliptical LG beams rises more rapidly as the propagation distance and the structural constant of the refractive index of the biological tissue increase and the beams become eventually more like Gaussian beams in the far-field under the influence of the turbulence biological tissues. Also, the numerical results proved that the effective beam spot radius increases as turbulence, wavelength, and propagation distance are increasing. Ultimately, the beams become circular under the influence of the turbulence of the biological tissue. As found that the effective beam spot radius along the x-axis becomes equal to that of the y-axis in high TBT which explain why an elliptical LG beam is converted into a circular one in higher structural constant of the turbulent tissue. Moreover, our results show that, the influence of the beam order m slightly greater than that of l on the beam spreading.

Highlights

In the past years, the propagations of the light beams affected by a turbulent medium have been extensively studied due to their interesting applications (Andrews and Phillips 1998; Baykal 2005)
In this work, we have employed a convenient way to derive the analytical formulae for the propagation and the effective beam spot radius of a coherent Laguerre-Gaussian (CLG) beam in turbulent biological tissues (TBT) based on the turbulence theories using the power spectrum refractive-index model
The numerical results of the propagation part demonstrated that the irradiance distribution profile of the coherent circular /elliptical LG beams eventually becomes like the Gaussian-distribution profile, in the far-field and under the powerful of tissue turbulence

Summary

Introduction

The propagations of the light beams affected by a turbulent medium have been extensively studied due to their interesting applications (Andrews and Phillips 1998; Baykal 2005). Optical vortex beams have always attracted much attention due to their wide applications (Molina-Terriza et al 2001; Yin et al 2003; Gibson et al 2004) and there are many methods to produce optical vortex family experimentally (Strohaber et al 2007, Tokizane et al 2009; Bekshaev et al 2012) In this regard, through any biological tissue, the treatment of circular and elliptical of hollow and anomalous hollow Gaussian beams (Saad and Belafhal 2017; Lu et al 2016) and the statistical properties of stochastic vortex beams (Luo et al 2014) have been investigated. A simple conclusion is outlined in the end of the paper

Expression formula of CLG beam at the source plane

Analytical formulae of CLG beam in TBT

Conclusion