Speaker
Description
This study reports on the growth and comprehensive characterization of pure and L-Valine amino acid–modified α-LiIO₃ single crystals, with an emphasis on structural features and nonlinear optical properties. High-quality nonlinear optical (NLO) α-LiIO₃ crystals from pure aqueous solution and α-LiIO₃ crystals from an aqueous solution containing L-Valine amino acid (5 mol%) were grown using the slow- evaporation method under controlled conditions. Structural analysis using single-crystal and powder X-ray diffraction indicates that the L-Valine additive is incorporated predominantly as defect centers or interstitial inclusions. Infrared spectroscopy further confirms the incorporation of functional groups characteristic of L-Valine into the α-LiIO₃ crystal.
Optical studies demonstrated improved transmittance in the visible region for α-LiIO_3:L-Val crystals and a significant reduction of the band gap attributed to the formation of additive-induced electronic states.
Notably, second-harmonic generation (SHG) efficiency increased for α-LiIO_3:L-Val crystal compared to pure α-LiIO_3. The observed enhancement is associated with modified electron density distribution and defect-mediated polarization effects.
The combined X-ray, spectroscopic, and SHG analyses demonstrate that amino acid additives provide an effective route for enhancement of optical and nonlinear optical properties in α-LiIO_3 crystals, making them promising candidates for photonic and optoelectronic applications.
Acknowledgments
This work was carried out within the framework of the project No. 25RG-2F039, provided by the Higher Education and Science Committee of the MESCS Republic of Armenia.