Nonlinear Optical Potential of Engineered Sodium D-Isoascorbate Monohydrate (NDIAM) Single Crystals: A Comprehensive Characterization Study

Abstract

Sodium D-Isoascorbate monohydrate (NDIAM) single crystals were successfully grown from slow cooling technique, and were found to have excellent structural quality, as confirmed by single crystal x-ray diffraction (SXRD) and powder XRD analyses. The crystals are extremely transparent in the visible to near-infrared region and a wide optical bandgap of 4.12 eV make them ideal for optical application that require low signal loss. The dielectric studies, along with theoretical polarizability models, indicate a strong dipolar response, which enhances the NLO interactions. Notably, the crystal shows negative photoconductivity, exhibits a thermal stability upto 160oC and a high laser damage threshold of 5.2 × 108 W/cm2, which supports its use in high power laser environments. Nonlinear optical (NLO) studies demonstrated that NDIAM possesses good second harmonic generation (SHG) efficiency, which is 1.85 times greater than the standard KDP crystal. Furthermore, third harmonic generation (THG) analysis shows that NDIAM has a positive refractive index and displays multi-phonon absorption behaviour.