Designing 1D grating for extraordinary optical transmission for TM polarization

Due to their high brightness at resonance, 1D metallo-dielectric transmission gratings have been proposed as useful in a number of applications including Scanning Near-field Optical Microscopy (SNOM), flat-panel displays, spatial light modulators and optoelectronic devices. In this article, using the Fabry-Perot resonance condition and numerical optimization, we demonstrate a design methodology of 1D grating structure that provides resonance at a desired wavelength for Transverse Magnetic (TM) polarization. Depending on grating and substrate materials and target applications under consideration, our method provides optimum grating parameters, i.e. slit width, grating period and thickness adaptively. Application specific requirements such as the bandwidth around a resonance can be adjusted by setting appropriate constraint functions. Simulations results from modal analysis show that resonances are achieved at wavelengths for which grating parameters have been optimized.