Rhodamine-6G organic films for optical limits: structural analysis, surface morphology, linear and nonlinear optical characteristics

Abstract

Rhodamine dyes have been used as a sensor and nonlinear optical materials. Rhodamine 6G (Rh6G) film has been deposited onto glass substrates by the spin coater system. The structural investigation using X-ray diffraction displayed that Rh6G films have an amorphous structure. The surface morphology by atomic force microscopy showed that Rh6G films have nanostructure with a grain size of 159 nm for the thickness of 125 nm, which slightly increased to 166 nm for the thickness of 304 nm. The indirectly allowed transitions with three energy gaps were evaluated to be 1.91, 2.86, and 3.68 eV for the thickness of 125 nm, which changed to 2.02, 2.96, and 3.68 eV for the thickness of 304 nm. Also, the nonlinear refractive index and third-order nonlinear susceptibility were estimated. Two different types of laser stud the response of Rh6G films as optical limiters. The reaction of Rh6G films is highly influential for the laser power attenuating of the green diode laser at 533 nm, and He–Ne laser at 632.8 nm indicated that probably a member for diverse nonlinear optical applications such as CUT-OFF laser filters.