Effect of l-cysteine on optical, thermal and mechanical properties of ADP crystal for NLO application

• The l-cysteine doped ADP crystal was grown by the slow evaporation technique.
• The grown crystal has high transmittance and improved optical band gap as 5.35 eV.
• Third order nonlinear susceptibility is 1.45×10−5 esu, vital for photonics devices.
• The SHG efficiency of grown crystal is two times that of KDP material.
• The grown crystal has optimum thermal stability up to 208 °C.

The ammonium dihydrogen phosphate (ADP) crystal doped with amino acid l-cysteine (LC) was grown by a slow evaporation technique. The grown crystal was transparent in the entire visible region, which is an essential requirement for a nonlinear crystal. The LC doping enhances the optical band gap of ADP (5.35 eV). The TG/DTA analysis of LC doped ADP crystal confirms the optimum thermal stability of grown crystal. The enhancement in the mechanical stability after LC doping was confirmed by Vicker׳s microhardness test. The LC doping showed significant impact on dielectric properties (dielectric constant and dielectric loss) of grown crystal. The third order nonlinear behavior of LC doped ADP crystal was investigated using a Z-scan technique at 632.8 nm and effective nonlinear optical parameters were evaluated.