【作者】 关星；

【导师】 王玉晓；

【作者基本信息】 哈尔滨工业大学 ， 光学， 2010， 硕士

【摘要】 激光与材料相互作用时表现出的非线性光学特性有着重要的应用,因此对材料的非线性光学特性以及光学非线性参数测量的研究受到了人们的广泛关注。NCO自由基是含氮燃料燃烧过程中重要的中间物之一,由于其本身的复杂性,它既存在电子振动相互作用（Renner-Teller效应） ,又存在ν₁′和2ν₂′之间的费米共振,使得该自由基团成为人们研究的热点。本论文我们应用速率方程理论和Z-扫描方法,研究了四种三能级模型:基态-激发态单光子吸收模型、基态单光子-双光子吸收并存模型、基态双光子吸收诱导激发态单光子吸收模型和单光子吸收诱导激发态双光子吸收模型的光学非线性吸收特性。讨论了NiNc（NCO）₄化合物的光学非线性吸收,主要包括NiNc（NCO）₄化合物的饱和吸收向反饱和吸收的转化和光学非线性吸收参数的测量。我们对上面述的四种三能级模型进行了稳态分析,研究表明只有单光子诱导激发态双光子吸收模型存在着饱和吸收向反饱和吸收转化的特征。再通过对单光子诱导激发态双光子模型进行动态分析,研究表明该模型还存在反饱和吸收向饱和吸收转化现象。这里我们详述了单光子诱导激发态双光子吸收模型产生饱和吸收和反饱和吸收相互转化的原因和条件。通过对NiNc（NCO）₄化合物的Z-扫描实验,并利用单光子诱导双光子吸收模型理论进行数据拟合,得到的实验曲线和理论拟合曲线符合的很好,证明了NiNc（NCO）₄化合物中单光子诱导激发态双光子吸收模型的有效性。更多还原

【Abstract】 Nonlinear optical properties, exhibited by the interaction between laser and materials, have important applications. Thus, the research on the nonlinear optical properties of materials and the measurement of optical nonlinear parameters is attracting wide attention. NCO free radical is one of important intermediates, which is produced from the Nitrogen-containing fuel combustion process. Due to its complexity—existing both veronica interaction （Renner-Teller Effect） and Fermi Resonance betweenν₁′and 2ν₂′, NCO free radical has become a focus for researchers.This thesis discussed the optical nonlinear absorption of the compound NiNc（NCO）₄, which included optical nonlinear conversion from saturable absorption to reverse saturable absorption and the measurement of optical nonlinearity absorption parameters. We used rate equation theory and the Z-scan method to study the optical nonlinear absorption properties of four kinds of three-level model, including the model of single photon absorption on ground state and excited state, the model of single-photon and two-photon absorption coexistence on ground state, the model of single-photon absorption on excited state induced by two-photon absorption on ground state and the model of two photon absorption on excited state induced by single photon absorption.The steady-state analysis on the above four models indicated that only the last one, the model of single-photon absorption induced two-photon absorption on excited state, had the conversion phenomena from saturable absorption to reverse saturable absorption. Dynamic analysis was implemented on the model of two-photon absorption on excited state induced by single-photon absorption, from which we found the conversion phenomena from reverse saturable absorption to saturable absorption is also exist. At last, we expanded on the reasons and conditions which resulted in these conversion.Through Z-scan experiment with NiNc（NCO）₄ compounds, compared with the data fit of the theoretic model of two-photon absorption on excited state induced by single-photon absorption, we found that the experimental curves agree well with the theoretical curves, demonstrating that the model of single-photon absorption induced two-photon excited state exist in NiNc（NCO）₄ compounds was effective.更多还原