Min Changjun, Yang Liu, Veronis Georgios
Center for Computation and Technology, Louisiana State University, Baton Rouge, Louisiana 70803, USA.
Opt Express. 2011 Dec 19;19(27):26850-8. doi: 10.1364/OE.19.026850.
We introduce a compact submicron structure consisting of multiple optical microcavities at both the entrance and exit sides of a subwavelength plasmonic slit filled with an absorbing material. We show that such microcavity structures at the entrance side of the slit can greatly enhance the coupling of the incident light into the slit, by improving the impedance matching between the incident plane wave and the slit mode. In addition, the microcavity structures can also increase the reflectivities at both sides of the slit, and therefore the resonant field enhancement. Thus, such structures can greatly enhance the absorption cross section of the slit. An optimized submicron structure consisting of two microcavities at each of the entrance and exit sides of the slit leads to ~9.3 times absorption enhancement at the optical communication wavelength compared to an optimized slit without microcavities.
我们引入了一种紧凑的亚微米结构，该结构由填充有吸收材料的亚波长等离子体狭缝的入口和出口两侧的多个光学微腔组成。我们表明，狭缝入口侧的这种微腔结构可以通过改善入射平面波与狭缝模式之间的阻抗匹配，极大地增强入射光与狭缝的耦合。此外，微腔结构还可以增加狭缝两侧的反射率，从而增强共振场。因此，这种结构可以极大地提高狭缝的吸收截面。与没有微腔的优化狭缝相比，由狭缝入口和出口两侧各两个微腔组成的优化亚微米结构在光通信波长处导致吸收增强约9.3倍。
