Optical Limiting Studies on Chalcone Doped PMMA Polymer Film

Abstract

An organic nonlinear optical (NLO) material (2E)-1-(3-chlorophenyl)-3-(3,4-dimethoxyphenyl)prop-2-en-1-one (CPDP) with molecular formula C17H15ClO3has been synthesized and crystallised in methanol solution. The crystals of CPDP were characterised by FTIR spectral technique. The various functional groups present in the crystal are identified. The thermal characteristics of the crystal were determined from the thermo gravimetric analysis (TGA) and differential scanning calorimetry(DSC) technique. CPDP crystals are thermally stable up to 115°C.Thin films of poly(methylmethacrylate) (PMMA) doped with CPDP were prepared on a clean corning glass substrate using a spin coater unit. N, N-dimethylformamide (DMF) is used as solvent. The surface characteristics of the film is studied using scanning electron microscope (SEM).Direct and indirect band gap energy of CPDP doped PMMA is determined using UV–Vis spectral response in the wavelength range 200-1100nm. Single beam Z-scan technique is used to study the nonlinear optical properties like nonlinear absorption coefficient and optical power limiting of the film using a nanosecond Nd-YAG laser operating at 532nm. The results of optical limiting studies show that the film possesses reverse saturable absorption (RSA) due to excited state absorption. The nonlinear optical properties of CPDP have been retained in the presence of PMMA making it a good candidate for optical power limiting applications.