Process and apparatus for the measurement of thermal radiation using regular glass optics and short-wave infrared detectors

1. A infrared detection apparatus, consisting of

a passive infrared detection apparatus assembly comprised of

a beam having a first shape;

at least one photosensor with a spectral filter to detect electromagnetic radiation only of critical wavelengths limited to the range of 2.0 μm to 2.5 μm;

at least one optical lens for conveying said electromagnetic radiation from an infrared-emitting source to said photosensor, wherein said optical lens is constructed from regular glass; and

a physical component for limiting background electromagnetic noise positioned between said infrared-emitting source and said photosensor through which said beam passes causing said beam to have a second shape,

wherein said detection apparatus emits no wavelengths.

2. The infrared detection apparatus of claim 1 , wherein said means for limiting background electromagnetic noise located between said infrared source and said photosensor is selected from a group consisting of a field stop, cut-on filter, shutter, a Lyot stop, a chopper and an active filter.

3. The infrared detection apparatus of claim 1 , wherein means for limiting background electromagnetic noise is a chopper.

4. The infrared detection apparatus of claim 3 wherein said chopper includes a reflective surface.

5. The infrared detection apparatus of claim 3 , which further includes an amplifier, and wherein said chopper frequency is close to the elbow of the 1/f noise spectrum of said amplifier.

6. The infrared detection apparatus of claim 3 , which further includes a field stop, wherein said chopper is close to said photosensor (in front of said field stop).

7. The infrared detection apparatus of claim 1 , wherein both visible light and infrared radiation are detected in the same said apparatus.

8. The infrared detection apparatus described in claim 1 , wherein said photosensor is capable of being cooled using thermoelectric coolers.

9. The infrared detection apparatus of claim 1 , wherein said photosensor is selected from a group of photosensors consisting of InGaAs and comprised of HgCdTe.

10. The infrared detection apparatus of claim 1 , which further includes an amplifier to amplify said photosensor's output.

11. The infrared detection apparatus of claim 10 , wherein said amplifier further includes adjustable (switchable) gains to maximize responsivity.

12. The infrared detection apparatus of claim 1 , which further includes an eyepiece through which said photosensor's output is directed through said eyepiece.

13. The infrared detection apparatus of claim 1 , wherein said at least one photosensor is arranged in a focal plane array.

14. The infrared detection apparatus of claim 1 , wherein said photosensor is selected for high shunt resistance.

15. The apparatus of claim 1 which further includes an infrared emitting source.

16. A process of detecting an infrared source, comprising:

directing SWIR towards at least one photosensor with sufficient senstivity to detect the incident SWIR at critical wavelengths limited to between 2.0 μm and 2.5 μm;

cooling said at least one photosensor using thermoelectric coolers;

amplifying said photosensor's output using an amplifier;

directing said photosensor's output through an eyepiece; and

measuring radiant power using said photosensor.

17. An infrared detection apparatus, wherein both visible and infrared radiation are detected in the same apparatus comprising:

a passive infrared detection apparatus assembly comprised of

at least one photosensor with a spectral filter to detect electromagnetic radiation of critical wavelengths limited to the range of 2.0 μm to 2.5 μm;

at least one optical lens for conveying radiation wherein said at least one optical lens is constructed of regular glass;

at least one amplifier; and

at least one physical component for limiting background electromagnetic noise located between said infrared-emitting source and said photosensor,

wherein said detection apparatus emits no wavelengths.