An investigation into the effects of electric field on the structural and optical properties of L-Cysteine doped KDP crystals

Abstract

Nowadays, different methods to grow large-size crystals are gaining more interest compared to traditional crystal growth techniques. Based on the applications, crystals must be modified and for that new crystal growth techniques must be introduced to meet such demands. Potassium Dihydrogen Phosphate (KDP) crystal is a well-known non-linear optical (NLO) crystal which has numerous demands in various fields, for instance, electro-optic devices, lasers, modulators, etc and due to which its habit modification plays a significant role in research and development. A slow evaporation technique was used to grow transparent and good-quality L-Cysteine (1 mol% and 2 mol%) doped KDP crystals; however, the crystals were grown in presence of a constant electric field at room temperature. With powder x-ray Diffraction (XRD) analysis and utilising FullProf Suite software, the crystal structure of the crystal was confirmed. The inclusion of L-Cysteine into KDP lattice was confirmed with fourier transform infrared (FTIR) spectroscopy. Optical transmittance spectra were recorded in the range of 200 and 800 nm. Photoluminescence (PL) studies were conducted in the range of 300–600 nm in order to detect lattice defects and intrinsic impurities. The value of relative second harmonic generation (SHG) efficiency was observed to be enhanced for crystals grown in presence of an electric field.