Controlling the optical properties of composite multilayered photonic structures: effect of superposition

Abstract

Tunability of the optical response of multilayered photonic structures has been compared with sequential (SQ) and superposition (SP) addition of refractive index profile functions. The optical response of the composite multilayered structure, formed after the SP addition of the two Bragg type refractive index profile functions has been studied as a function of percentage overlap and relative shift between the profiles. Apart from the substantial advantage in terms of the reduced physical thickness of the SP composite structures (over the SQ addition), at certain optimum values of relative shift, photonic structures with better quality factor resonant modes or a broader PBG could be designed. Similar analysis has been extended for rugate filters as well. The experimental verification of the optical response, was carried out through multilayered dielectric porous silicon structures fabricated by electrochemical anodization.

Ultrathin, broadband, omnidirectional, and polarization-independent infrared absorber using all-dielectric refractory materials

“…As shown in the inset of Figure 1(E), an average absorption of >95% was achieved from 5 to 18 μm at an incident angle ≤50°for both s-and p-polarized light. Using effective medium theory and the transfer matrix method [34], we calculated the reflectance and transmittance of our devices. Figure 1(E) depicts the calculated absorption spectra for s-and p-polarized light as dashed lines.…”