Gratings and their quasistatic equivalents for high optical absorbance
Résumé
We consider thin lamellar and cylinder gratings, composed of silicon carbide and air, and investigate the conditions under which they can totally absorb an incident plane wave, for both p and s polarizations. We also consider thin-film equivalent in the quasi-static limit to the gratings, deriving the effective dielectric tensor for cylinder gratings. We show that the accuracy of the quasi-static model is a strong function of polarization, wavelength, and grating thickness due to the resonant nature of the optical constants of silicon carbide but that these models can be quantitatively accurate and give a good qualitative guide to the parameter values under which thin gratings can deliver high optical absorptance.