Investigation of the Diffraction Ring Patterns of Chlorophyll Using Spatial Self-phase Modulation Technique

Abstract

In this paper, the formation of the diffraction ring patterns at far field of chlorophyll was studied as a result of the Spatial Self-Phase modulation (SSPM) of the CW laser beam with λ=532 nm.The SSPM technique was used to determine several of nonlinear optical parameters such as the nonlinear optical refractive index n₂ and the thermo-optic coefficient dn/dT.

The evolution time of the formed diffraction rings was also investigated, the compression effect on the diffraction rings was observed with the increase in laser irradiation time on the studied sample, which was explained by the thermal convention currents and the gravitational effect.