利用带相位物体的非简并泵浦探测方法测量了一种新型菁类化合物溶液在皮秒时域的非线性光学性质。 在接近材料线性吸收峰值的 532 nm 皮秒激光脉冲泵浦下,利用 600 nm 的皮秒激光脉冲作为探测光,测量了菁染料分子在近共振区的非线性折射动力学响应。 结合相关理论,通过数值模拟最终确定了菁染料分子在 600 nm 波段的光物理参数。 实验结果表明:该溶液的非线性光学效应来自于溶质菁染料分子的激发态非线性机制,该材料具备了较大的激发态折射体积,且单重激发态的寿命较短。 该化合物具备非线性光学应用潜力。
The nonlinear refraction dynamics of a novel cyanine dye/DMF solution was investigated using time-resolved nondegenerate pump-probe system with phase object at pico-second timescale. The 532 nm laser pulse with 21-ps duration was used as the excitation and the laser pulse of 600 nm with 10-ps duration was used for probing. The experimental results show that the nonlinear optical response of cyanine solution originates from solute molecule's excited-state nonlinear mechanism. The experiment curve is interpreted by numerical simulations based on a five-energy-level model and all of nonlinear optical parameters of cyanine dye at 600 nm are determined. This cyanine dye exhibits large change of refraction index per unit density for excited-state as well as short lifetime, indicating this compound can be a good candidate for future photonic applications.