A semi-organic nonlinear optical crystal of L-threonine silver nitrate (LTSN) was successfully cultivated using a slow evaporation solution growth method at ambient temperature. The grown LTSN crystals were thoroughly characterized through various methods like single crystal and powder X-ray diffraction (XRD), UV–Vis–NIR spectroscopy, FTIR, thermal analysis, microhardness, dielectric measurements, laser damage threshold (LDT), second harmonic generation (SHG), third-order generation, and etching analysis. XRD results reveal that the LTSN crystallizes in a monoclinic system with a non-centrosymmetric space group of P21. FT-IR spectroscopy confirmed the presence of all expected functional groups. Remarkable thermal stability up to 210 °C is analyzed by thermogravimetric and differential thermal (TG/DT) analysis. A deep mechanical analysis was carried out to understand the complete mechanical behavior of the grown material. The UV–Vis–NIR study showed excellent optical transparency in the entire visible region, with a lower cut-off wavelength of 283 nm and an optical band gap Eg = 4.33 eV. In addition, optical parameters like extinction coefficient, reflectance, and linear refractive index are also calculated for the cultivated material. The laser damage threshold analysis was carried out on the surface of the cultivated material, and it was found to be 5.86 GW/cm2. The SHG efficiency of LTSN crystal reveals an efficiency 4.38 times higher than standard. The investigation of third-order nonlinear optical characteristics and optical limiting behavior was performed utilizing the Z-scan method with a continuous-wave (CW) laser operated at 532 nm. Nonlinear parameters such as refractive index (n2), absorption coefficient (β) and third-order nonlinear optical susceptibility (χ(3)). The findings indicated significant χ(3) values of 2.889 × 10–08 esu, along with an optical limiting threshold noted at 2.427 × 103 Wcm−2. Capacitance and dissipation factor (DF) were analyzed at room temperature in the frequency range 50 Hz–5 MHz. The dielectric constant for the grown LTSN crystal remains constant for the entire frequency range studied. The growth mechanism and quality of the grown crystal were analyzed by etching analysis. In summary, the results of these studies suggest that the synthesized L-threonine silver nitrate-derived material possesses potential for use in optical limiting, switching, and optoelectronic applications.

Growth mechanism and physicochemical properties of L-threonine silver nitrate (LTSN) single crystal for frequency doubling and optical limiting applications

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发表日期：

2026年2月4日

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S. E. Allen Moses,
J. Johnson,
P. Nagaraju,
S. E. Annie Jasmine

摘要

A semi-organic nonlinear optical crystal of L-threonine silver nitrate (LTSN) was successfully cultivated using a slow evaporation solution growth method at ambient temperature. The grown LTSN crystals were thoroughly characterized through various methods like single crystal and powder X-ray diffraction (XRD), UV–Vis–NIR spectroscopy, FTIR, thermal analysis, microhardness, dielectric measurements, laser damage threshold (LDT), second harmonic generation (SHG), third-order generation, and etching analysis. XRD results reveal that the LTSN crystallizes in a monoclinic system with a non-centrosymmetric space group of P2₁. FT-IR spectroscopy confirmed the presence of all expected functional groups. Remarkable thermal stability up to 210 °C is analyzed by thermogravimetric and differential thermal (TG/DT) analysis. A deep mechanical analysis was carried out to understand the complete mechanical behavior of the grown material. The UV–Vis–NIR study showed excellent optical transparency in the entire visible region, with a lower cut-off wavelength of 283 nm and an optical band gap E_g = 4.33 eV. In addition, optical parameters like extinction coefficient, reflectance, and linear refractive index are also calculated for the cultivated material. The laser damage threshold analysis was carried out on the surface of the cultivated material, and it was found to be 5.86 GW/cm². The SHG efficiency of LTSN crystal reveals an efficiency 4.38 times higher than standard. The investigation of third-order nonlinear optical characteristics and optical limiting behavior was performed utilizing the Z-scan method with a continuous-wave (CW) laser operated at 532 nm. Nonlinear parameters such as refractive index (n2), absorption coefficient (β) and third-order nonlinear optical susceptibility (χ⁽³⁾). The findings indicated significant χ⁽³⁾ values of 2.889 × 10^–08 esu, along with an optical limiting threshold noted at 2.427 × 10³ Wcm⁻². Capacitance and dissipation factor (DF) were analyzed at room temperature in the frequency range 50 Hz–5 MHz. The dielectric constant for the grown LTSN crystal remains constant for the entire frequency range studied. The growth mechanism and quality of the grown crystal were analyzed by etching analysis. In summary, the results of these studies suggest that the synthesized L-threonine silver nitrate-derived material possesses potential for use in optical limiting, switching, and optoelectronic applications.