High time-resolution ultrasensitive optical detector, using grating coupling

• US 7,763,854 B2
• Filed: 09/26/2007
• Issued: 07/27/2010
• Est. Priority Date: 10/05/2006
• Status: Expired due to Fees

• Current Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Original Assignee: Commissariat a L'Energie Atomique (AES Corporation)
• Inventors: Frey, Laurent
• Primary Examiner(s): Porta; David P
• Assistant Examiner(s): Malevic; Djura
• Application Number:
  US11/861,876
• Publication Number:
  US 20090020701A1
• Time in Patent Office: 1,035 Days
• Field of Search: 250/336.2, 250/338.1, 250/370.01, 385/14, 385/37, 385/129
• US Class Current: 250/336.2
• CPC Class Codes: G01J 1/02 Details
• CPC Class Codes: G01J 1/0209 Monolithic
• CPC Class Codes: G01J 1/04 Optical or mechanical part supplementary adjustable parts
• CPC Class Codes: G01J 1/0407 Optical elements not provided otherwise, e.g. manifolds, windows, holograms, gratings
• CPC Class Codes: G01J 1/42 using electric radiation detectors optical or mechanical part G01J1/04; by comparison with a reference light or electric value G01J1/10

Abstract

This detector is intended to detect at least one photon and comprises a dielectric substrate (30), of index n_O; a detecting element (32) forming a serpentine, placed on the substrate and generating a signal using the energy of the photon(s); a dielectric grating, formed of lines of index n_H, alternating with lines of index n_B, avec n_H>n_O and n_H>n_B, the grating being placed above the detecting element, the set grating-element presenting a resonant absorption in a given incidence and for a given polarisation; and a superstratum (40) having a refractive index n_i, this superstratum being placed above the one-dimensional dielectric grating, n_H being furthermore greater than n_i.

Claims

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

a dielectric substrate, having a refractive index n_O, 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 n_H, and second lines that alternate with the first lines and that are made of a dielectric medium having a refractive index n_B, 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), n_H being greater than n_O and n_B, and

a superstratum having a refractive index n_i, this superstratum being placed above the one-dimensional dielectric grating, n_H being furthermore greater than n_i.

2. Optical detector set forth in claim 1, wherein the given incidence is a normal incidence.

3. Optical detector as claimed in claim 1, wherein the superstratum is a gas, especially air, a liquid, a solid or a vacuum.

4. Optical detector as claimed in claim 1, wherein pitch Λ

of the one-dimensional dielectric grating is less than λ

_O/n_O, where λ

_O represents the wavelength in vacuum of the photon(s), and pair (w_r/Λ

, d) is selected to lead to a resonant absorption, where w_r represents the width of the first lines of the one-dimensional dielectric grating and d represents the thickness of this one-dimensional dielectric grating, and Λ

is furthermore less than λ

_O/n_i.

5. Optical detector as claimed in claim 1, wherein the difference n_H−

n_B is greater than 1.

6. Optical detector as claimed in claim 1, wherein the detecting element (32) is made of a superconducting material.

7. Optical detector as claimed in claim 1, wherein the serpentine includes parallel lines, connected to each other, and each line of the serpentine is positioned facing one of the lines of the one-dimensional dielectric grating.

8. Optical detector as claimed in claim 1, wherein the serpentine includes parallel lines, connected to each other, and each line of the serpentine is positioned facing one of the first lines of the one-dimensional dielectric grating.

9. Optical detector as claimed in claim 1, wherein the serpentine includes parallel lines, connected to each other, and lines of the serpentine and the first lines of the one-dimensional dielectric grating have the same width and form periodic units having the same period.

10. Optical detector as claimed in claim 1, wherein the first lines of the one-dimensional dielectric grating have different widths w_rL and w_rS and the first lines whose width equals w_rL alternate with the first lines whose width equals w_rS.

11. Optical detector as claimed in claim 1, wherein the second lines of the one-dimensional dielectric grating have different widths.

12. Optical detector as claimed in claim 1, further comprising an intermediary layer which is made of a dielectric material having a refractive index n greater than n_B and which is placed between the detecting element and the one-dimensional dielectric grating.

13. Optical detector, intended to detect one photon or photons, this optical detector including a polarisation splitter including an input port, intended to receive the photon(s), and two output ports which are respectively connected to two optical detectors as claimed in claim 1.

14. Optical detector including a matrix of optical detectors as claimed in claim 1.