Investigation of nonlinear optical properties for laser dyes-doped polymer thin film | ||
| Iraqi Journal of Physics | ||
| Article 1, Volume 10, Issue 19, December 2012, Pages 54-69 | ||
| Authors | ||
| Zainab F. Mahdi; Ahmed A. Ali | ||
| Abstract | ||
| Solutions of dyes Rhodamine 6G (Rh6G) and Coumarin480(C480) were prepared at five concentrations (1x10-3, 5x10-4, 1x10-4, 5x10-5 and1x10-5) mol/l, the mixing was stirred to obtain on a homogenous solution, the(poly methyl-methacrylate) (PMMA) was solved by chloroform solvent with certain ratio, afterward (PMMA+Rh6G) and (PMMA+C480) thin films were prepared by casting method on glass block which has substrate with dimensions (7.5 x2.5)cm2, the prepared samples were left in dark place at room temperature for 24 hours to obtain uniform and homogenous thin films. UV-VIS absorption spectra, transmission spectra and fluorescence spectra were done to measure linear refractive index and linear absorption coefficient. The nonlinear optical properties of the prepared thin films were measured by z-scan technique. Two cases were measured: the first case is the closed-aperture z-scan to measure the nonlinear refractive index and the second case is open-aperture z-scan to measure the nonlinear absorption coefficient. The two cases were performed at two wavelengths 532 nm and 1064 nm and at two input fluences. For thin film (PMMA+ C480) the results show that the nonlinear absorption coefficient is directly proportional with the input fluence and directly proportional with increasing a concentration of the dye, while for thin film (PMMA+Rh6G) the nonlinear absorption coefficient inversely proportional with the input fluence and directly proportional with increasing a concentration of the dye. For thin films (PMMA+C480) and (PMMA+Rh6G) the nonlinear refractive index is inversely proportional to the input fluence. For both thin films the nonlinear absorption coefficient is more affected at wavelength 1064 nm and the nonlinear refractive index is more affected at wavelength 532nm. | ||
| Keywords | ||
| Rhodamine; Coumarin; nonlinear optical properties | ||
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