High-order optical nonlinearities in nanocomposite films dispersed with semiconductor quantum dots at high concentrations

Photorefractive Photonics 2017

Tomita, Yasuo^1 ; Matsushima, Shun-Suke^1 ; Yamagami, Ryu-Ichi^1 ; Jinzenji, Taka-Aki^1 ; Sakuma, Shohei^1 ; Liu, Xiangming^1,2 ; Izuishi, Takuya^1 ; Shen, Qing^1

Department of Engineering Science, University of Electro-Communications, Tokyo

182-8585, Japan^1

Research Center of Laser Fusion, Chinese Academy of Engineering Physics, Mianyang

621900, China^2

关键词: Electron hole recombination process;    Femtosecond pump probes;    Grating measurement;    Inorganic-organic nanocomposites;    Intensity-dependent;    Non-linear optical properties;    Optical nonlinearity;    Refractive non-linearity;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/867/1/012011/pdf
DOI  :  10.1088/1742-6596/867/1/012011

来源: IOP

【 摘 要 】

We describe the nonlinear optical properties of inorganic-organic nanocomposite films in which semiconductor CdSe quantum dots as high as 6.8 vol.% are dispersed. Open/closed Z-scan measurements, degenerate multi-wave mixing and femtosecond pump-probe/transient grating measurements are conducted. It is shown that the observed fifth-order optical nonlinearity has the cascaded third-order contribution that becomes prominent at high concentrations of CdSe QDs. It is also shown that there are picosecond-scale intensity-dependent and nanosecond-scale intensity-independent decay components in absorptive and refractive nonlinearities. The former is caused by the Auger process, while the latter comes from the electron-hole recombination process.