Ultrafast Thermal Nonlinearity.
Ultrafast Thermal Nonlinearity.
复制标题
DOI：
10.1038/srep17899
复制
发表时间：
2015-12-08
影响因子：
4.6
通讯作者：
Tsai DP
中科院分区：
文献类型：
--
作者：
Khurgin JB;Sun G;Chen WT;Tsai WY;Tsai DP
在上半个世纪中探索的三阶非线性光学现象已经被预测在生活的许多行业中找到广泛的应用，例如全光开关、路由等，然而这一前景尚未实现，主要是因为当非线性效应发生在当今信号处理应用所需的皮秒尺度上时，非线性效应的强度太低。最强的三阶非线性，产生的热效应，被认为是太慢，上述应用。在这项工作中，我们表明，当光场集中到几十纳米尺度的体积，热光效应的速度接近皮秒尺度。这种亚衍射极限的场集中可以通过使用浸渍热光电介质（例如，非晶Si）的金属纳米颗粒中的等离子体效应来实现，并且导致足以用于超快尺度上的所有光学切换的相移。
Third order nonlinear optical phenomena explored in the last half century have been predicted to find wide range of applications in many walks of life, such as all-optical switching, routing, and others, yet this promise has not been fulfilled primarily because the strength of nonlinear effects is too low when they are to occur on the picosecond scale required in today’s signal processing applications. The strongest of the third-order nonlinearities, engendered by thermal effects, is considered to be too slow for the above applications. In this work we show that when optical fields are concentrated into the volumes on the scale of few tens of nanometers, the speed of the thermo-optical effects approaches picosecond scale. Such a sub-diffraction limit concentration of field can be accomplished with the use of plasmonic effects in metal nanoparticles impregnating the thermo-optic dielectric (e.g. amorphous Si) and leads to phase shifts sufficient for all optical switching on ultrafast scale.