Large Third-Order Optical Nonlinearities in Brilliant Green Solutions Induced by CW He-Ne Laser

Laser induced third-order nonlinear optical responses of Brilliant Green solution (which belongs to triphenylmethane organic dye group) was investigated by utilizing single beam Z-scan technique using a continuous wave He-Ne laser at the wavelength of 632.8 nm. It was observed that the material exhibits self-defocusing and saturation absorption type optical nonlinearity behavior. The measurements of the real and imaginary parts of the third-order nonlinear optical susceptibility were carried out at several incident laser irradiations and different dye concentrations. It was found that the increase in any of the incident laser intensity or solution concentration leads to the linear increase of the nonlinear refractive index. The obtained values of the third-order nonlinearities of Brilliant Green solutions are amongst the highest reported CW regimes, to the best of our knowledge. This study shows a great potential of the Brilliant Green for the application in nonlinear optical devices.