Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application, School of Physical Science and Technology, Suzhou University of Science and Technology, Suzhou 215009, China.
Department of Physics, Soochow University, Suzhou 215123, China.
Molecules. 2023 Jun 10;28(12):4692. doi: 10.3390/molecules28124692.
Broadband reverse saturable absorption is systematically investigated via Z-scan, transient absorption spectrum (TAS). The excited state absorption and negative refraction of Orange IV are observed in the Z-scan experiment at 532 nm. Meanwhile, two-photon-induced excited state absorption and pure two-photon absorption are observed at 600 nm and 700 nm with the pulse width of 190 fs, respectively. An ultrafast broadband absorption in the visible wavelength region is observed via TAS. The different nonlinear absorption mechanisms at multiple wavelengths are discussed and interpreted from the results of TAS. In addition, the ultrafast dynamics of negative refraction in the excited state of Orange IV are investigated via a degenerate phase object pump-probe, from which the weak long-lived excited state is extracted. All studies indicate that Orange IV has the potential to be further optimized into a superior broadband reverse saturable absorption material and also has certain reference significance for the study of optical nonlinearity in organic molecules containing azobenzene groups.
通过 Z 扫描和瞬态吸收光谱（TAS）系统地研究了宽带反饱和吸收。在 532nm 的 Z 扫描实验中观察到了橙色 IV 的激发态吸收和负折射。同时，在 600nm 和 700nm 处观察到了双光子诱导的激发态吸收和纯双光子吸收，脉宽分别为 190fs。通过 TAS 观察到可见光波长范围内的超快宽带吸收。从 TAS 的结果讨论和解释了多个波长下不同的非线性吸收机制。此外，通过简并相位物体泵浦探测研究了橙色 IV 激发态中的超快负折射动力学，从中提取了弱长寿命激发态。所有研究表明，橙色 IV 有可能进一步优化为一种优异的宽带反饱和吸收材料，并且对含偶氮苯基团的有机分子的光学非线性研究也具有一定的参考意义。
