非线性介电常数近零材料:基于时变热能的诠释

Nonlinear epsilon-near-zero material: Explanation with time-varying thermal energy

近年来,具备介电常数近零(Epsilon-Near-Zero, ENZ)特性的透明金属氧化物材料及其在非线性光学领域的应用吸引了国内外学者的广泛关注.人们通常认为ENZ材料中的巨大光学非线性的物理根源是激光泵浦下透明金属氧化物材料导带内自由电子等效质量的巨大变化.最近的一项研究通过引入时变电子热能的概念,更完善地诠释了ENZ材料的瞬态非线性光学响应,相关理论得到了实验的验证.

In recent years, transparent conducting oxides with epsilon-near-zero(ENZ) response and their associated applications in nonlinear optics have drawn wide attention of the research community. It is commonly thought that the physical origin of the giant optical nonlinearity in ENZ materials is the large change of effective mass of free electrons within the conduction band of the transparent conducting oxide material. In a recent study, by introducing the concept of timevarying thermal energy, the transient nonlinear optical response of ENZ material is more thoroughly explained. The theory is further corroborated by experimental studies.