High time-resolution ultrasensitive optical detector, using grating coupling

Optical detector, intended to detect at least one photon, this detector comprising:

• a dielectric substrate, having a refractive index nO, and
• a detecting element forming a serpentine, the detecting element being placed on the dielectric substrate and designed to generate an electric signal using the energy of the photon(s) received,
• this optical detector being characterised in that it further comprises
• a one-dimensional dielectric grating, including parallel lines, namely first lines that are made of a first dielectric material having a refractive index nH, and second lines that alternate with the first lines and that are made of a dielectric medium having a refractive index nB, the one-dimensional dielectric grating being placed above the detecting element, the set constituted by the one-dimensional dielectric grating and the detecting element presenting resonant absorption of the photon(s), at a given incidence and for a given polarisation of the photon(s), nH being greater than nO and nB, and
• a superstratum having a refractive index ni, this superstratum being placed above the one-dimensional dielectric grating, nH being furthermore greater than ni.