Nonlinear absorption, optical limiting behavior and structural study of a new chalcone derivative-1-(3, 4-dimethylphenyl)-3-[4 (methylsulfanyl) phenyl] prop-2-en-1-one T. Chandra Shekhara Shetty a , S. Raghavendra a,b,n , C.S. Chidan Kumar c , S.M. Dharmaprakash a a Department of Studies in Physics, Mangalore University, Mangalagangotri 574199, India b Department of Engineering Physics, Adichunchanagiri Institute of Technology, Jyothinagaar, Chikmagalore, Karnataka 577102, India c Department of Engineering Chemistry, Alva’s Institute of Engineering & Technology, Visvesvaraya Technological University, Mijar, Moodbidri 574225, Karnataka, India article info Article history: Received 20 May 2015 Received in revised form 18 August 2015 Accepted 21 August 2015 Keywords: Crystal growth Optical materials X-ray diffraction Optical limiting abstract A new third order nonlinear optical (NLO) organic material-1-(3, 4-dimethylphenyl)-3-[4(methylsulfa- nyl) phenyl] prop-2-en-1-one (4DPMS) belonging to chalcone family has been crystallized in acetone solution. The 4DPMS crystals are characterized by CHNS analysis, FTIR, UV–visible spectral and thermal techniques. The single crystal X-ray diffraction study reveals that 4DPMS crystallizes in monoclinic system with P2 1 /n space group. The linear optical absorption spectrum revealed that the 4DPMS crystals are transparent in the entire visible region. Thermogravimetric data shows absence of phase transition before melting point and from differential scanning calorimetry analysis the melting point of the crystal is found to be 106 °C. Third order nonlinear absorption and optical limiting experiment on 4DPMS was carried out using open aperture Z-scan technique with Nd: YAG laser operating at 532 nm. It was found that the calculated values of excited state absorption cross section for 4DPMS molecules is much greater than the ground state absorption cross section. A decrease in effective nonlinear absorption coefficient was observed with increase in the input irradiance of laser. The observed optical limiting property in 4DPMS is attributed to reverse saturable absorption. & 2015 Elsevier Ltd. All rights reserved. 1. Introduction Organic nonlinear optical (NLO) materials exhibiting third or- der optical nonlinearity plays a significant role in the photonic technology [1–4]. To improve the performance and efficiency of photonic devices, researchers have sought for new organic mate- rials with enhanced NLO characteristics [3–5]. The organic mate- rials have the combined advantage of high optical nonlinearity and versatility of synthesis route to engineer the molecular structure to maximize the optical nonlinearity. In general the modified op- tical properties of the materials due to high intense laser are di- vided into nonlinear absorption (NLA) and nonlinear refraction (NLR) changes. The NLA changes are commonly described by equation α ¼ α o þ βI, where α is linear absorption coefficient; β is a nonlinear absorption coefficient and I is the intensity of the laser [6]. The NLA coefficient includes reverse saturation absorption (RSA), two photon absorption (TPA) and saturation absorption (SA). A large number of organic materials have been found to ex- hibit laser induced absorption changes [7–9]. Among organic materials, chalcones and their derivatives have recently attracted much attention due to ease of molecular structure design and synthetic flexibility that can offer the modification of nonlinear response. Generally, the nonlinear absorption and optical limiting behavior of organic materials are investigated using nanosecond laser pulses. This paper describes resonant nonlinear optical ab- sorption spectrum and material characteristics of a new organic molecule: 1-(3, 4-dimethylphenyl)-3-[4-(methylsulfanyl) phenyl] prop-2-en-1-one (4DPMS), belonging to chalcone family. 2. Materials and methods 2.1. Synthesis and crystallization The title compound was synthesized as per the procedure re- ported earlier [10]. 3, 4-dimethyl acetophenone (0.01 mol) and 4- (methylthio) benzaldehyde (0.01 mol) (from Sigma Aldrich) were Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/optlastec Optics & Laser Technology http://dx.doi.org/10.1016/j.optlastec.2015.08.015 0030-3992/& 2015 Elsevier Ltd. All rights reserved. n Corresponding author at: Department of Engineering Physics, Adichunchanagiri Institute of Technology, Jyothinagara, Chikmagalore, Karnataka 577102, India. E-mail address: raghuphotonics@gmail.com (S. Raghavendra). Optics & Laser Technology 77 (2016) 23–30