Third order nonlinear optical properties of CdSe quantum dot doped liquid crystal was studied in both isotropic and nematic state. CdSe quantum dots were synthesized by kinetic growth method. The optical and morphological analysis provided confirmation of the quantum dot formation. Nonlinear optical properties of the samples were explored by a single beam Z scan technique using Q-switched Nd:YAG laser, delivering pulses at 532 nm and 7 ns pulse width. Nonlinear optical absorption was found to be enhanced significantly on increasing the concentration of quantum dots in the liquid crystal. Janossy effect and charge transfer mechanism play a crucial role in the observed enhancement. The obtained values of the nonlinear refractive index, n₂ and the third order optical susceptibility, χ⁽³⁾ were of the order of 10⁻¹⁰ m²/W and 10⁻¹¹ esu, respectively. The optical limiting thresholds of the studied systems are found to be 1.57 J/cm² (isotropic) and 2.1 J/cm² (nematic). The nonlinear optical characteristics of the CdSe-liquid crystal blend validate its application as an optical limiter.

研究了CdSe量子点掺杂液晶在各向同性和向列状态下的三阶非线性光学性质。通过动力学生长法合成了CdSe量子点。光学和形态学分析证实了量子点的形成。通过使用Q开关Nd：YAG激光器的单束Z扫描技术探索了样品的非线性光学特性，并在532 nm和7 ns的脉冲宽度下提供了脉冲。发现非线性光学吸收随着增加液晶中量子点的浓度而显着增强。詹诺西效应和电荷转移机制在观察到的增强中起关键作用。所获得的非线性折射率n ₂和三阶光学磁化率χ ^{（3）的值}分别为10 ^-10  m ² / W和10 ^-11  esu。发现所研究系统的光学极限阈值为1.57 J / cm ²（各向同性）和2.1 J / cm ²（向列）。CdSe-液晶共混物的非线性光学特性验证了其作为光学限幅器的应用。