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.

 
OptL-Sakat2013a.png
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
OptL-Sakat2013b.png
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.
OptL-Sakat2013c.png
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).