One-mode model for patterned metal layers inside integrated color pixels

Optimized design of the optical f ilters inside integrated color pixels (ICPs) for complementary metal-oxide semiconductor image sensors requires analytical models. ICP optical f ilters consist of subwavelength patterned metal layers. We show that a one-mode model, in which subwavelength gaps in the metal layer are described in terms of single-mode waveguides, suff ices to predict the salient features of measured ICP wavelength selectivity. The Airy-like transmittance formula, derived for transverse-electric polarization, predicts an angle-independent cutoff wavelength, which is in good agreement with predictions made with a twodimensional f inite-difference time-domain method. © 2004 Optical Society of America OCIS codes: 050.0050, 050.2770, 110.2970, 130.3120, 260.2110.