Micro-optics for optical imager with non-uniform filter

1. An optical system, comprising:

a bulk receiver optic configured to receive light rays originating from a field external to the optical system; and

an optical assembly having a plurality of micro-optic receiver channels defining a plurality of discrete, non-overlapping fields of view in the field, the optical assembly comprising:

an aperture layer having a plurality of discrete apertures arranged along a focal plane of the bulk receiver optic;

an array of photosensors disposed behind the aperture layer; and

a non-uniform optical filter layer configured to allow different micro-optic channels to measure different ranges of wavelengths;

wherein the optical assembly further comprises a plurality of lenses, each channel further including a lens from the plurality of lenses, and wherein the lens for each channel is axially aligned with and configured to collimate lights rays received through its corresponding aperture and pass the collimated light rays into its corresponding photosensor.

2. The optical system set forth in claim 1 wherein the non-uniform optical filter comprises a graduated optical filter.

3. The optical system set forth in claim 2 wherein the graduated optical filter gradually increases in thickness in one dimension.

4. The optical system set forth in claim 2 wherein the graduated optical filter increases in thickness in a step-wise fashion in one dimension such that each channel has a constant optical filter layer thickness, but wherein the thicknesses for different micro-optic channels are different.

5. The optical system set forth in claim 1 wherein the array of photosensors comprises an array of photodetectors with each photodetector comprising an array of single-photon avalanche detectors (SPADs).

6. The optical system set forth in claim 1 wherein each channel includes an aperture from the plurality of discrete apertures, and a photosensor in the array of photosensors.

7. The optical system set forth in claim 1 wherein the lens for each channel is configured as a hemisphere positioned along a path of light from the bulk receiver optic, wherein the optical filter is coated on a curved surface of the lens.

8. The optical system set forth in claim 1 wherein the photosensor in each channel comprises a plurality of single-photon avalanche detectors (SPADs).

9. An optical system, comprising:

a bulk receiver optic configured to receive light rays originating from a field external to the optical system; and

an optical assembly having a plurality of micro-optic receiver channels defining a plurality of discrete, non-overlapping fields of view in the field, the optical assembly comprising:

an aperture layer having a plurality of discrete apertures arranged along a focal plane of the bulk receiver optic;

a plurality of lenses;

an array of photosensors disposed behind the aperture layer; and

a non-uniform optical filter layer configured to allow different micro-optic channels to measure different ranges of wavelengths;

wherein each channel includes an aperture from the plurality of discrete apertures, a lens from the plurality of lenses and a photosensor in the array of photosensors, the photosensor comprising a plurality of single-photon avalanche detectors (SPADs);

wherein the lens for each channel collimates lights rays received through its corresponding aperture and passes the collimated light rays into its corresponding photosensor; and

each channel further comprises a second plurality of lenses that corresponds in number to the plurality of SPADs and wherein each lens in the second plurality of lenses focuses incident photons received at the photosensor on an individual SPAD in the plurality of SPADs in the channel.

10. An optical system, comprising:

a bulk receiver optic configured to receive light rays originating from a field external to the optical system; and

an optical assembly having a plurality of micro-optic receiver channels defining a plurality of discrete, non-overlapping fields of view in the field, the optical assembly comprising:

an aperture layer having a plurality of discrete apertures arranged along a focal plane of the bulk receiver optic;

an array of photosensors disposed behind the aperture layer; and

a non-uniform optical filter layer configured to allow different micro-optic channels to measure different ranges of wavelengths;

wherein the optical assembly comprises a monolithic ASIC constructed on a common substrate, within which the array of photosensors are fabricated, and the separate layers for the aperture layer, a plurality of lenses, and the filter layer are formed on the monolithic ASIC such that they become part of the monolithic structure of the ASIC.

11. The optical system set forth in claim 10 wherein each of the separate layers for the aperture layer, the plurality of lenses, the filter layer and the array of photosensors is bonded to its adjacent layer.

12. An optical system comprising:

a bulk receiver optic configured to receive light from a field external to the optical system;

an aperture layer disposed behind the bulk optic and including a plurality of apertures located at a focal plane of the bulk optic;

a lens layer including a plurality of collimating lenses having a focal length, the lens layer disposed behind the aperture layer and separated from the aperture layer by the focal length;

a non-uniform optical filter layer behind the lens layer; and

a photosensor layer including a plurality of photosensors;

wherein the aperture layer, lens layer, non-uniform optical filter layer and photosensor layer are arranged to form a plurality of micro-optic channels defining a plurality of discrete, non-overlapping fields of view in the field with each micro-optic channel in the plurality of micro-optic channels including an aperture from the plurality of apertures, a lens from the plurality of lenses, a filter from the filter layer, and a photosensor from the plurality of photosensors and being configured to communicate light incident from the bulk receiver optic to the photosensor of the micro-optic channel; and

wherein the non-uniform optical filter layer is configured to allow different micro-optic channels to measure different ranges of wavelengths.

13. The optical system set forth in claim 12 wherein the non-uniform optical filter comprises a graduated optical filter.

14. The optical system set forth in claim 13 wherein the graduated optical filter gradually increases in thickness in one dimension.

15. The optical system set forth in claim 13 wherein the graduated optical filter increases in thickness in a step-wise fashion in one dimension such that each channel has a constant optical filter layer thickness, but wherein the thicknesses for different micro-optic channels are different.

16. An optical system, comprising:

a bulk receiver optic configured to receive light rays originating from a field external to the optical system; and

an optical assembly having a plurality of micro-optic receiver channels defining a plurality of discrete, non-overlapping fields of view in the field, the optical assembly comprising:

a monolithic ASIC including a processor, a memory, and a plurality of photosensors fabricated in the ASIC;

an aperture layer having a plurality of discrete apertures arranged along a focal plane of the bulk receiver optic, the array of photosensors disposed behind the aperture layer;

a plurality of lenses positioned between the aperture layer and the array of photosensors; and

a non-uniform optical filter layer configured to allow different micro-optic channels to measure different ranges of wavelengths, wherein the aperture layer, plurality of lenses, and non-uniform optical filter layer are formed on the ASIC such that they form part of the monolithic structure of the ASIC.

17. The optical system set forth in claim 16 wherein the micro-optic receiver channels are configured such that each micro-optic receiver channel is paired with a light emitter of a plurality of light emitters.

18. The optical system set forth in claim 16 wherein the non-uniform optical filter comprises a graduated optical filter.

19. The optical system set forth in claim 18 wherein the graduated optical filter gradually increases in thickness in one dimension.

20. The optical system set forth in claim 1 wherein a sensing area of each photosensor in the plurality of photosensors is larger than an area of its corresponding aperture in the plurality of apertures.

21. The optical system set forth in claim 12 wherein a sensing area of each photosensor in the array of photosensors is larger than an area of its corresponding aperture in the plurality of apertures.