Abstract

The isoniazid-vanillin hybrid (IVH), a Schiff base compound is synthesized and its vibrational spectral properties, structural, linear and third-order nonlinear optical (TNLO) characteristics are studied. IVH is examined by ¹H and ¹³C NMR, FT-IR and mass spectroscopic techniques. Solvent dependent TNLO properties are studied by Z–scan technique for which a 5 mW power CW diode laser with 650 nm wavelength is used. The order of nonlinear refractive index (n₂) and nonlinear absorption coefficient (β) is measured to be 10⁻⁷ cm²/W and 10⁻³ cm/W, respectively. The sample exhibits both positive and negative nonlinear absorption coefficient owing to the phenomenon of saturable and reverse saturable absorption, as well as negative nonlinear index of refraction as a result of self-defocusing. Self-defocusing is the result of thermal nonlinearity owing to the continuous absorption of light source. The real and imaginary component of the TNLO susceptibility of the sample is found to be the order of 10⁻⁷ esu. The order of TNLO susceptibility (χ⁽³⁾) of IVH in polar solvents is measured to be 10⁻⁷ esu. The effect of solvent spectral features on χ⁽³⁾ is also discussed. The results show that, the organic compound IVH is a promising candidate for applications in nonlinear optics.

中文翻译：

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异烟肼-香草醛杂化物的振动光谱、结构、线性和三阶非线性光学性质

摘要

合成了席夫碱化合物异烟肼-香草醛杂化物（IVH），并研究了其振动光谱性质、结构、线性和三阶非线性光学（TNLO）特性。^{IVH 通过1} H 和¹³ C NMR、FT-IR 和质谱技术进行检查。通过 Z 扫描技术研究了溶剂依赖性 TNLO 特性，该技术使用波长 650 nm 的 5 mW 功率 CW 二极管激光器。测得非线性折射率(n ₂ )和非线性吸收系数(β)的量级分别为10 ^-7 cm ² /W和10 ^-3  cm/W。由于可饱和和反饱和吸收现象，样品呈现正和负非线性吸收系数，以及由于自散焦而呈现负非线性折射率。自散焦是由于光源的连续吸收而产生热非线性的结果。发现样品的 TNLO 磁化率的实部和虚部为 10 ^-7 esu 量级。极性溶剂中IVH的TNLO磁化率(χ ⁽³⁾ )测量为10 ^-7 esu。还讨论了溶剂光谱特征对 χ ⁽³⁾的影响。结果表明，有机化合物IVH在非线性光学中具有广阔的应用前景。