Development of Nano Plasmonic Structures for Multispectral IR Filters
Technical Report,10 May 2013,09 May 2017
North Carolina Central University Durham United States
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Our computations of the optical transmission of a rectangular hole array1 with the finite difference time-domain FDTD 2 method show that the transmission peak is dependent on the periodicities of the array the polarization of the incident plane wave is very crucial for a high transmission when the polarization is parallel to the short ridge of the rectangle hole, it yields high optical transmission. The hole aspects are very important to the transmission too, the length longer side of a rectangular hole is decisive to the magnitude and bandwidth of the transmission and the width shorter side of the hole has little effect on the peak magnitude, but has effect on the peak location and the thickness of the metal film can be treated as the length of a Fabry-Perot cavity. Multi-modes of light from these metallic structures can be obtained by increasing the metal film thickness. Cross-shaped-hole arrays CSHAs are selected3 to diminish the polarization-dependent transmission differences of incident plane waves. The transmission spectrum of a multispectral filter consists of CSHAs is shown in figure 1 top left, in this simulation, the length and width of the rectangular hole for the CSHA are set to 280nm and 50nm for period of 350nm, respectively and the thicknesses of the metal films are set to 100nm. We varied the period by increasing 50nm for each periodicity, and the length of CSHAs is 0.8 of the period, meantime, the width of the rectangular hole and the thickness of the gold film are kept as constant. The simulations show that the transmission peak is shifting gradually as the periodicity is increasing by 50nm from 350nm to 750nm. The fabrication procedures of these metallic structures are crucial. various available methods are studied for the best results.
- Electricity and Magnetism
- Miscellaneous Materials
- Atomic and Molecular Physics and Spectroscopy