Crystal growth, optical, thermal, mechanical and third-order nonlinear optical properties of L-lysine hydrochloride-doped sulphamic acid single crystals for optical applications

L-lysine hydrochloride-doped sulphamic acid (SA) crystals have been grown by slow evaporation technique. X-ray diffraction experiments confirmed the orthorhombic structure of SA crystal. The doped crystals have high transmission than the pure SA crystal. TG and DTA studies exhibit the title crystals are thermal stability up to 212 °C (pure), 210 °C (1 mol%) and 207 °C (2 mol%). The enhancement of the hardness value in the doped crystal was confirmed by the hardness test. The etch pit density was measured using chemical etching study. The photosensitivity of the grown crystals is 0.10 (pure), 0.36 (1 mol%) and 0.72 (2 mol%). The laser damage threshold (LDT) analyses show that the L-lysine hydrochloride-doped SA crystals have more LDT value than the pure SA crystal. Third-order NLO susceptibility was found to be 5.004, 5.864 and 6.050 × 10–10 esu for pure and L-lysine hydrochloride-doped (1 and 2 mol %) SA crystals, respectively.