Room-temperature quantum noise limited spectrometry and methods of the same

1. A method of forming a plasmonic condensing lens for room temperature quantum noise limited (QNL) infrared (IR) spectrometry, the method comprising:

forming a silicon cone on a substrate;

coating the silicon cone with a highly reflective material; and

modifying the silicon cone using focused ion beam (FIB) modification to permit transmittance of light through the silicon cone.

2. The method as recited in claim 1 , wherein forming the silicon cone on the substrate comprises reactive ion etching.

3. The method as recited in claim 1 , wherein the highly reflective material is selected from a group consisting of Au, Ag, Pt and Cu.

4. The method as recited in claim 1 , wherein the substrate comprises SiO 2 .

5. The method as recited in claim 1 , wherein modifying the silicon cone using FIB produces a silicon cone characterized by an aperture diameter approximately one-seventh ( 1/7) that of a wavelength of light that is to be detected by a detector coupled to the silicon cone.

6. The method as recited in claim 5 , wherein the detector is placed in direct contact with the aperture of the silicon cone.

7. The method as recited in claim 1 , wherein the silicon cone is formed to have dimensions including a length of about 10 μm, a diameter at a receiving end of about 3.5 μm, and a diameter at a transmitting end of about 0.5 μm.

8. The method as recited in claim 1 , comprising installing the plasmonic condensing lens in a heterodyne detection system for detecting light, the system comprising:

a first input aperture configured to receive first light from a scene input;

a second input aperture configured to receive second light from a local oscillator input;

a broadband local oscillator configured to provide the second light to the second input aperture;

a dispersive element configured to disperse the first light and the second light; and

the plasmonic condensing lens coupled to an infrared detector,

wherein the plasmonic condensing lens is configured to concentrate incident light from a primary condensing lens onto the infrared detector,

wherein the infrared detector is a square-law detector configured to sense a frequency difference between the first light and the second light; and

wherein each area of the first and second input apertures times an input collection solid angle of the system is about a wavelength squared (about λ 2 ).

9. The method as recited in claim 1 , comprising installing the plasmonic condensing lens in a heterodyne detection system for detecting light, the system comprising:

a first input aperture configured to receive first light from a scene input;

a second input aperture configured to receive second light from a local oscillator input;

a broadband local oscillator configured to provide the second light to the second input aperture;

a dispersive element configured to disperse the first light and the second light; and

the plasmonic condensing lens coupled to an infrared detector;

wherein the plasmonic condensing lens is configured to concentrate incident light from a primary condensing lens onto the infrared detector;

wherein the infrared detector is a square-law detector configured to sense a frequency difference between the first light and the second light;

wherein the plasmonic condensing lens has a conical shape tapering inward toward the infrared detector; and

wherein the conical shape has a first diameter at an end adjacent the infrared detector of less than about one-half wavelength of the incident light in Si, and wherein the conical shape has a second diameter at an end receiving the incident light from the dispersive element of approximately a diffraction limit set by the primary condensing lens.

10. The method as recited in claim 1 , comprising installing the plasmonic condensing lens in a heterodyne detection system for detecting light, the system comprising:

a first input aperture configured to receive first light from a scene input;

a second input aperture configured to receive second light from a local oscillator input;

a broadband local oscillator configured to provide the second light to the second input aperture;

a dispersive element configured to disperse the first light and the second light; and

the plasmonic condensing lens coupled to a detector;

wherein the plasmonic condensing lens is configured to concentrate incident light from a primary condensing lens onto the detector; and

wherein the detector is detector configured to sense a frequency difference between the first light and the second light.