Metal–dielectric bi-atomic structure for angular-tolerant spectral filtering


We theoretically study metal–dielectric structures made of bi-atomic metallic gratings coupled to a guided-mode dielectric resonator. The bi-atomic pattern grating allows tailoring of the Fourier spectrum of the inverse grating permittivity in order to adapt the frequency gap and obtain a flat dispersion band over a wide angular range. A significant enhancement (two-fold) of the angular tolerance as compared to a simply periodic structure is obtained.

a) Simply Periodic metallic Grating (SPG) filter. (b) Normal incidence transmission of filters with SPG on both sides (dark) and on one side (green). (c) Bi-atomic metallic grating-based filter. (d) Dispersion relation for (blue) unperturbed and (red) perturbed guide-mode
Calculated angle-resolved transmission diagrams as a function of the wavenumber σ and of the incident wavevector for two bi-atomic structures; d=3 μm, td=700 nm, tm=100 nm. (a) a=200 nm and l=500 nm. (b) a=300 nm and l=600 nm.
Transmission at λR=4.02 μm as a function of the incidence angle for one SPG structure and one bi-atomic structure. Transmission spectra at different incidence angle for (b) the SPG structure and for (c) the bi-atomic structure.

Contact: Jean-Luc Pelouard

Further Reading: E. Sakat et al. Opt. Lett 38, 425 (2013).