1-[4-(methylsulfanyl) phenyl]-3-(4-nitropshenyl) prop-2-en-1-one: A reverse saturable absorption based optical limiter

An organic nonlinear optical material “1-[4-(methylsulfanyl) phenyl]-3-(4-nitrophenyl) prop-2-en-1-one” (4MPNP) has been synthesized by Claisen-Schmidt condensation and crystallized by slow evaporation technique at ambient temperature. The functional groups present in 4MPNP molecule were identified by FTIR spectroscopy. TGA-DSC analysis in the temperature range 30oC-650 °C showed absence of phase transition before melting point. The crystal structure of 4MPNP was determined using X-ray single crystal diffraction technique. UV-Vis absorption studies were carried out in the wavelength range 190-800 nm. Beyond the cut off wavelength 4MPNP is optically transparent in the entire visible region of the spectrum. Open aperture Z-Scan experimental curve showed that the 4MPNP molecule exhibits minimum transmittance at the focus and maximum nonlinear absorptionat532 nm wavelength. The variation of normalized transmittance with laser power density indicates good optical limiting behavior of the molecule. Nonlinear optical absorption coefficient (β), excited state absorption cross-section (σex) and ground state absorption cross-section (σg) are estimated and found to be 4.5 cm/GW, 5.17 × 10−18 cm2 and 5.68 × 10−21 cm2 respectively. The values σex>>σg indicate that 4MPNP crystal has the property of reverse saturable absorption. The studies recommend that 4MPNPcan be considered as a potential material for third order nonlinear optical device applications such as optical limiters.