1 3 DOI 10.1007/s00340-016-6478-9 Appl. Phys. B (2016) 122:205 Crystal structure and nonlinear optical absorption of a new chalcone derivative: a promising candidate for optical switching T. Chandra Shekhara Shetty 1,2 · S. Raghavendra 3 · C. S. Chidan Kumar 4 · S. M. Dharmaprakash 1 Received: 11 July 2015 / Accepted: 21 June 2016 © Springer-Verlag Berlin Heidelberg 2016 1 Introduction In the field of photonics, materials exhibiting nonlin- ear optical (NLO) properties have potential applications in optical switching, optical data storage, processing of information by wavelength multiplexing, modulating the phase as well as frequencies of the optical signal, etc. In this regard, the organic materials, because of their syn- thetic flexibility, ultrafast response and large optical non- linearities over their inorganic counterparts, play a major role [1–4]. The requirement of molecular feature for NLO property and the failure of symmetry carryover from mol- ecule to crystal are discussed in the literature [5]. The NLO and electro-optic properties of the organic materials can be modified by varying the donor/acceptor groups at the ends of a parent molecule [6]. Similarly by substituting various functional groups, their optical properties can be fine-tuned. Such compounds exhibit large values of molecular hyper- polarizability [7, 8]. Chalcone has a π-conjugated system. Due to overlapping of π orbital, delocalization of electronic charge distribution leads to a high mobility of the electron density [9]. The presence of appropriate terminal electron donor or acceptor groups on aromatic ring can enhance the asymmetric electron distribution in either or both ground and excited electron states, leading to large molecular hyperpolarizabilies and good crystallizability [10]. Mate- rials having fast response time, high linear transmittance, low limiting threshold, etc. show intensity-dependent non- linear absorption called optical limiting property. Such properties of optical limiting are useful in optical sensors and protection of human eye against high intensity. The third-order nonlinearities are useful in high-frequency ultrafast optical processing techniques [11–13]. Five deriv- atives of dibenzylideneacetone synthesized by Kiran et al. [14] showed very high third-order optical nonlinearities Abstract A new nonlinear optical material, 4-[(2E)-3-(3- fluorophenyl) prop-2-enoyl] benzonitrile (3FPB), belong- ing to chalcone family was synthesized and characterized by FTIR and linear absorption spectroscopy. Single-crystal X-ray diffraction reveals that the new material crystallizes in monoclinic system with P2 1 /c space group and lattice param- eters a = 6.4841(2) Å, b = 13.6038(5) Å, c = 14.6418(6) Å, α = 90.00°, β = 94.552(2)° and γ = 90°. The crystal- lographic perfection of the synthesized material has been analyzed by X-ray powder diffraction. The X-ray powder diffraction peaks of the sample were indexed with hkl values. The UV–visible spectrum for 3FPB crystals showed the opti- cal transmittance window and a lower cutoff wavelength of absorption at 343 nm. The direct transition band gap energy and indirect transition energy gap were determined using Tauc’s plots. The thermal stability and melting point of the material have been investigated by thermogravimetric analy- sis/differential thermal analysis (TGA/DTA). The Thermo- gravimetric curve showed the absence of any phase transi- tion before melting point. Third-order nonlinear absorption and optical limiting experiment were carried out using open- aperture Z-scan experiment with Nd:YAG laser nanosecond pulses at a wavelength of 532 nm. * T. Chandra Shekhara Shetty smdharma@yahoo.com; tcsshetty@gmail.com 1 Department of Studies in Physics, Mangalore University, Mangalagangotri 574199, India 2 Department of Post Graduate Studies in Physics, St Aloysius College (Autonomous), Mangalore 575003, India 3 Department of Physics, Adichunchanagiri Institute of Technology, Jyothinagaar, Chikmagalore 577102, India 4 Department of Chemistry, Alva’s Institute of Engineering and Technology, Visvesvaraya Technological University, Mijar, Moodbidri, Karnataka 574225, India