Electromagnetic cavity able to support Tamm modes

1. A Tamm electromagnetic cavity possessing a resonant frequency in the THz domain, comprising:

an interference mirror that is reflective in the THz domain, the interference mirror comprising a stack of dielectric layers comprising an alternation, in a z-direction, of two different layers, a layer of high refractive index and a layer of low refractive index, the refractive index of the layer of low refractive index being lower than that of the refractive index of the layer of high refractive index, and being manufactured by stacking layers mechanically or by joining dielectric layers to one another; and

an upper metal layer deposited on or added to an upper dielectric layer of said interference mirror so as to form a structure that supports at least one Tamm mode in the THz domain, the upper metal layer being structured so as to form an antenna possessing a resonant frequency equal to that of the electromagnetic cavity.

2. The electromagnetic cavity as claimed in claim 1 , wherein the upper metal layer is continuous.

3. The electromagnetic cavity as claimed in claim 1 , wherein the upper metal layer is structured so as to control the transverse mode and the polarization of the one or more Tamm modes.

4. The electromagnetic cavity as claimed in claim 1 , wherein the structured upper metal layer forms a bow-tie antenna, a patch antenna, a dipole antenna, or a split-ring resonator.

5. The electromagnetic cavity as claimed in claim 1 , wherein at least one of the layers of low refractive index of the interference mirror is formed by a spacer separating two layers of high refractive index so as to obtain a layer of air between two layers of high refractive index.

6. The electromagnetic cavity as claimed in claim 1 , wherein the dielectric layers are made of high-resistivity silicon, of semi-insulating GaAs or of quartz, or are made of a polymer film.

7. The electromagnetic cavity as claimed in claim 1 , comprising a layer referred to as the mirror layer, above the upper metal layer and separated by a dielectric layer, said mirror layer comprising a lower metal layer and an upper carrier layer, wherein the upper metal layer is a layer of superconductor.

8. The electromagnetic cavity as claimed in claim 1 , comprising an active element of a characteristic size comprised between 1 and 100 microns, placed in the cavity so as to be able to be coupled to the Tamm mode excited in said cavity.

9. The electromagnetic cavity as claimed in claim 8 , wherein the active element is placed within a layer of air of the interference mirror, said layer being located below the upper dielectric layer.

10. The electromagnetic cavity as claimed in 8 , wherein the active element is made of graphene.

11. The electromagnetic cavity as claimed in claim 10 , comprising a metal layer referred to as the electrode making electrical contact with the graphene active element and connected to an electrical circuit configured to apply a gate voltage to said graphene active element.

12. A method for using an electromagnetic cavity as claimed in claim 1 , comprising:

illuminating said cavity with incident radiation propagating in said z-direction at a THz frequency equal to the resonant frequency of said cavity; and

exciting a Tamm mode at a resonant frequency of the cavity.

13. A Tamm electromagnetic cavity possessing a resonant frequency in the THz domain, comprising:

an interference mirror that is reflective in the THz domain, the interference mirror comprising a stack of dielectric layers comprising an alternation, in a z-direction, of two different layers, a layer of high refractive index and a layer of low refractive index, the refractive index of the layer of low refractive index being lower than that of the refractive index of the layer of high refractive index, and being manufactured by stacking layers mechanically or by joining dielectric layers to one another; and

an upper metal layer deposited on or added to an upper dielectric layer of said interference mirror so as to form a structure that supports at least one Tamm mode in the THz domain, the upper metal layer being structured so as to form a grating of metal strips of width s and of period p, separated by a distance a, and of fill factor ff=s/p with p=s+a.

14. The electromagnetic cavity as claimed in claim 13 , wherein the fill factor ff of the grating of metal strips varies in the x-direction so as to allow a plurality of different THz frequencies of incident radiation to be coupled to said electromagnetic cavity.

15. The electromagnetic cavity as claimed in claim 13 , wherein at least one of the layers of low refractive index of the interference mirror is formed by a spacer separating two layers of high refractive index so as to obtain a layer of air between two layers of high refractive index, the electromagnetic cavity comprising an active element of a characteristic size comprised between 1 and 100 microns, placed in the cavity so as to be able to be coupled to the Tamm mode excited in said cavity.

16. The electromagnetic cavity as claimed in claim 13 , wherein the dielectric layers are made of high-resistivity silicon, of semi-insulating GaAs or quartz, or are made of a polymer film.

17. The electromagnetic cavity as claimed in claim 13 , comprising a mirror layer, above the upper metal layer and separated by a dielectric layer, said mirror layer comprising a lower metal layer and an upper carrier layer, wherein the upper metal layer is a layer of superconductor.

18. A method for using an electromagnetic cavity as claimed in claim 13 , comprising:

illuminating said cavity with incident radiation propagating in said z-direction at a THz frequency equal to the resonant frequency of said cavity; and

exciting a Tamm mode at a resonant frequency of the cavity.