| The phenomenon of EOT(Enhanced Optical Transmission) through the metal film with periodic subwavelength hole arrays has a wide range of applications, can achieve nano-scale control of light in optical integrated circuits, and can be more and more used in optoelectronics and sensor technologies.This paper focuses on the transmission phenomenon of new structure, subwavelength hole arrays of metal thin film on Bragg gratings.For the physical mechanism of this EOT, conclusions tend to be followings, one is SPR (Surface Plasmons Resonance) due to periodical array of holes; another is waveguidance resonance in each single hole. Experiments show that these two mechanisms produce transmission peaks are independent.Bragg structure is essentially comprised of alternating layers of high and low-refractive dielectrics, it strongly reflects a band of wavelength depending on the thickness of periodic unit and refractive indices of the constituting layers, will have two reasons effective control of the transmission peaks.Finite difference time domain method (FDTD) numerical simulation of electromagnetic fields is getting more and more attention. This method can solve directly the discretized Maxwell equations in the time domain, and simulate any structure of arbitrary geometry; another advantage is that it can process the impulse response into the pulse Fourier transforms in a large frequency range.In this paper, we used FDTD method in three-dimensions, taking 10nm for the grid size, Perfect Matched Layers (PML) as absorbing boundaryParts, to simulate and calculate the results of light transmitting through the periodic hole array metal film and Bragg gratings... |
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