Chettiar Uday K, Engheta Nader
Opt Express. 2015 Jan 12;23(1):445-51. doi: 10.1364/OE.23.000445.
Vanadium dioxide (VO(2)) is a material that undergoes thermal phase transition resulting in drastic changes in its material properties. The phase change can also be brought on by optical pumping. Several experimental results have been presented in the literature dealing with such phase transitions brought on by optical pumping. In this manuscript we present a theoretical framework, which addresses this problem by self consistently solving the electromagnetic problem and the thermodynamic problem using a multiphysics approach when such transitions are thermally mediated, as is the case with continuous-wave optical pumps. Such an analysis provides us with insights into the transition process and also helps explain the conditions under which some of the observed experimental results like bistability takes place. Such optically induced phase transition materials also present the intriguing possibility of ultrahigh nonlinearity where the input optical signal essentially converts a dielectric into a plasmonic material. These materials can find significant applications in nonlinear metatronics.
二氧化钒（VO₂）是一种会发生热相变的材料，其材料特性会因此发生剧烈变化。这种相变也可以通过光泵浦来引发。文献中已经给出了一些关于光泵浦引发此类相变的实验结果。在本论文中，我们提出了一个理论框架，当此类相变由热介导时（如连续波光泵浦的情况），该框架通过使用多物理场方法自洽地求解电磁问题和热力学问题来解决这个问题。这样的分析为我们提供了对转变过程的见解，也有助于解释一些观察到的实验结果（如双稳性）发生的条件。这种光致相变材料还呈现出超高非线性的有趣可能性，即输入光信号基本上能将一种电介质转化为等离子体材料。这些材料在非线性超材料中有重要应用。
