Experimental and computational perspectives on linear and non-linear optical parameters of an orthorhombic crystal for optical limiting applications

• Published in: Applied physics. A, Materials science & processing Materials science & processing, 2020, Vol.126 (1), Article 56
• Main Authors: Ravi, Sarath, Sreedharan, Rakhi, Raghi, K. R., Manoj Kumar, T. K., Naseema, K.
• Format: Article
• Language: English
• Subjects: Applied physics; Characterization and Evaluation of Materials; Charge transfer; Condensed Matter Physics; Constraining; Crystal growth; Cut off wavelength; Density functional theory; Diamond pyramid hardness tests; Dielectric properties; Figure of merit; Functional groups; KDP crystals; Laser damage; Linearity; Machines; Manufacturing; Materials science; Nanotechnology; Nonlinearity; Optical activity; Optical and Electronic Materials; Optical properties; Organic crystals; Parameters; Photonics; Physics; Physics and Astronomy; Potassium phosphates; Processes; Single crystals; Surfaces and Interfaces; Switching; Thin Films
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-019-3234-0

4-Dimethylaminopyridinium 3,5-dinitrobenzoate (DMAPDNBA), a charge transfer complex, was synthesized and successfully grown by slow evaporation solution growth technique. Single-crystal X-ray diffractogram reveals that the material crystallizes in orthorhombic system with non-centrosymmetric space group P2 1 2 1 2 1 with cell parameters a  = 5.92 Å, b  = 13.77 Å, c  = 18.64 Å, and V  = 1519 Å 3 . Powder XRD and FTIR spectral investigation were carried out to analyse the crystallinity of the material and for assigning vibrations to identify the different functional groups existing within the material. The optical transmittance in the visible and near IR (400–800 nm) regions with lower cutoff wavelength of 227 nm, luminescence spectrum, and the optical band gap of 5.45 eV sufficiently fulfilled the requirement for non-linear optical applications. The thermal exploration analysis (TG–DSC) confirmed the stable nature of the compound up to 190 °C, and dielectric constant measurement of the obtained sample enhanced the property of non-linear optical activity at higher frequencies. The mechanical property of DMAPDNBA was evaluated using Vickers’s hardness test which confirmed that the material belonged to the soft category. The frequency conversion efficiency of the grown sample was measured to be eightfold that of the reference potassium dihydrogen phosphate, which exploits the potentiality of the charge transfer complex to be used as a promising candidate for various laser-assisted NLO applications. Third-order non-linearity was measured adopting Z-Scan technique, and the optical limiting/switching efficiency of the complex was verified with the optical limiting threshold value of 10.64 J/cm 2 and figure of merit property, confirming the capability of the material for switching applications. The threshold value of laser damage was found to be 1.74 GW/cm 2 . Theoretical investigations were performed using density functional theory (DFT-B3LYP) approach to estimate and predict various linear and non-linear optical properties of the DMAPDNBA complex. The first-order hyperpolarizability value of the DMAPDNBA molecule was found to be 19 times that of the standard organic crystal, urea. In short, all the above findings designate the candidature of the charge transfer complex, DMAPDNBA, for photonic applications.