Abstract Ammonium dihydrogen phosphate (ADP) is an important nonlinear optical (NLO) material used for electro-optical applications and finds various NLO applications using Nd:YAG and Nd:YLF Lasers. The Amino acids have properties like molecular chirality and zwitter ionic nature helps to improve NLO properties of ADP. The pure and l -threonine doped ADP crystals are grown using slow solvent evaporation technique at room temperature. The Powder XRD spectra suggest tetragonal crystal system and slight shifting of peak. The FT-IR spectra verify the presence of various functional groups of pure and doped ADP crystals. The FT-Raman shows strong absorption peak at 922 cm −1 due to asymmetric stretching of PO 4 3− for all samples without shifting indicating the single phase nature of all samples. The photoluminescence study suggests the presence of defects in doped samples compared to the pure one due to increase of Stokes shift and vibrational energy relaxation phenomena. The presences of constituent elements are indentified using CHN analysis. The optical transmittance, energy band gap, skin depth, refractive index and extinction coefficient is study using UV–Visible spectroscopy and the dispersive behaviour of refractive index below absorption edge is study using Wemple-DiDomenico single oscillator model. The variation of capacitance and conductance is study using complex admittance spectroscopy. All the grown crystals have possessed negative photoconductivity. The second and third harmonic generation efficiency is increased nearly to double for l -threonine doped ADP crystals compared to pure Potassium dihydrogen phosphate (KDP). The laser damage threshold is measure for pure and doped ADP crystals.

中文翻译：

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L-苏氨酸对磷酸二氢铵晶体生长及性能的影响

摘要 磷酸二氢铵 (ADP) 是一种重要的非线性光学 (NLO) 材料，用于电光应用，并发现使用 Nd:YAG 和 Nd:YLF 激光器的各种非线性光学 (NLO) 应用。氨基酸具有分子手性和两性离子性质等特性，有助于改善 ADP 的 NLO 特性。在室温下使用缓慢溶剂蒸发技术生长纯的和 l-苏氨酸掺杂的 ADP 晶体。粉末 XRD 谱表明四方晶系和峰的轻微移动。FT-IR 光谱验证了纯 ADP 晶体和掺杂 ADP 晶体的各种官能团的存在。由于所有样品的 PO 4 3- 的不对称拉伸，FT-拉曼在 922 cm -1 处显示出强吸收峰，没有移动，表明所有样品的单相性质。光致发光研究表明，与纯样品相比，由于斯托克斯位移和振动能量弛豫现象的增加，掺杂样品中存在缺陷。使用 CHN 分析确定构成元素的存在。使用紫外-可见光谱研究光学透射率、能带隙、趋肤深度、折射率和消光系数，使用 Wemple-DiDomenico 单振荡器模型研究吸收边缘以下折射率的色散行为。使用复导纳光谱研究电容和电导的变化。所有生长的晶体都具有负光电导性。与纯磷酸二氢钾 (KDP) 相比，掺杂 l-苏氨酸的 ADP 晶体的二次和三次谐波产生效率几乎增加了一倍。