Habit modification in L-arginine doped potassium dihydrogen phosphate crystal growth under applied electric field

Abstract

Potassium Dihydrogen Phosphate (KDP) is a non-linear optical (NLO) crystal well known over many years. Now-a-days it has become more popular because of its combination with organic materials forming new NLO material called semi-organics. We have investigated the habit change of L-Arginine doped KDP crystals in presence of constant d. c. electric field. Pure and L-Arginine (1 mol%) doped KDP crystals were grown with slow evaporation method at room temperature in presence as well as in absence of the electric field. The characteristics of the crystals obtained were studiedusing Fourier Transform Infrared (FTIR) spectroscopy, Second Harmonic Generation (SHG) efficiency test and Photoluminiscencespectra. The relative habit modification observedin the crystals grown under electric field is probably due to inclusion and adsorption of L-Arginine ions in the presence of electric field in the prismatic section of crystal. The FTIR spectra obtained of the crystalswere analyzedto identify functional groups present in the crystals. Photoluminescence spectra were used to assess presence of intrinsic impurities through color centres and to identify lattice defects. The SHG efficiency was found to have increased in the cases of both the doped crystals grown in presence of electric field and in absence of electric field.