High time-resolution ultrasensitive optical sensor using a planar waveguide leakage mode, and methods for making same

An optical detector, configured to detect at least one photon, the detector comprising:

• a stacking with a dielectric substrate having a refractive index nS and, including on the substrate:
• a detection element configured to generate an electrical signal from the energy of the at least one photon received, and
• a first dielectric layer having a refractive index nH;
• a second dielectric layer, placed on the first dielectric layer and having a refractive index nB, nH being greater than nB and nS, the detection element being placed between the substrate and the first dielectric layer or between the first and second dielectric layers, the first dielectric layer constituting a light guide, configured to guide the at least one photon, the energy of which is then in part absorbed by the detection element, and
• a dielectric superstrate that has a refractive index nP, nP being greater than nS and nB, and which is placed on the second dielectric layer and is configured to send the at least one photon into the light guide,
• wherein respective thicknesses of the first and second dielectric layers enable a resonant coupling between the at least one photon and a leakage mode of the light guide, the stacking having an absorption resonance linked to the leakage mode, for a given polarization of the at least one photon.