The Theoretical Study of TM Transmittance and Contrast Ratio for Sub-Wavelength Metallic Gratings

According to the requirement of the bionic navigation sensitive wave band of 380nm~520nm for sub-wavelength metallic gratings, in order to achieve performance indicators under the basic structural parameters. Analyzing TM transmittance and contrast ratio is carried out by employing finite-difference time-domain (FDTD) method. The result reveals that height, slit width and dielectric of grating impact TM transmittance and contrast ratio in various extents, and the greatest influence on the TM transmittance and contrast ratio is slit dielectric and slit width respectively.