Angular Response of Logically Combined Photonic Crystals

When we logically combine two one-dimensional photonic crystals of slightly different periodicities, the resulting doubly resonant optical structure possesses dense number of localized modes along the axis of periodicity (on-axis). This paper investigates the angular response of such logically combined photonic crystals (LCPCs), and shows that the on-axis localized modes of the LCPCs can be excited using an off-axis light, over a broad range of incident angles. This enables a greater flexibility in the excitation of the localized modes, and consequently broadens the applications of the LCPCs. We present the frequency dispersion and the tunability of the quality factors of the localized modes, with respect to the off-axis angle, polarization, and the background medium's refractive index.