Parametric Dependence of Thermal Lensing-Induced Phase Changes in Carbon Tetrachloride on Laser Power and Sample Thickness

Thermal lensing is one of the important nonlinear effects in transparent optical media, which results in a spatial change in the refractive index and ultimately the divergence or convergence of the beam as a result of partial absorption of the laser beam and its conversion into heat. In this study, the thermal lensing effect in carbon tetrachloride, as a medium with a negative optical-thermal coefficient, was investigated, focusing on the dependence of the beam phase angle on the two parameters of cell thickness and laser power. The results showed that the phase angle becomes continuously more negative with increasing sample thickness and laser power; in other words, its absolute value increases, which confirms the increase in thermal gradient and the strengthening of the beam divergence behavior at higher powers. These results can be used as a basis for optimizing the design of optical systems sensitive to phase changes, including optical detectors, amplifiers, and precision optical systems.

کلیدواژه ها:

Nonlinear optical ، Phase changes ، Thermal lensing Effect ، Z-scan