Optical device comprising wavelength-selective optical filter including downconverter

1. An optical system, comprising:

an optical sensor;

a plurality of photosensitive pixels disposed on the optical sensor;

a wavelength-selective optical filter in optical communication with the photosensitive pixels, the wavelength-selective optical filter being disposed remotely from the optical sensor; and

a plurality of spatially-variant areas disposed in the optical filter, at least one area of the plurality of spatially-variant areas including a downconverter,

wherein the wavelength-selective optical filter comprises first and second filter sheets, the first filter sheet defining therein at least one first written region and at least one first non-written region, the second filter sheet defining therein at least one second written region and at least one second non-written region, the plurality of spatially-variant areas comprising:

an area of the at least one first written region overlapping with an area of the at least one second non-written region;

an area of the at least one first non-written region overlapping with an area of the at least one second written region; and

an area of the at least one first written region overlapping with an area of the at least one second written region.

2. The optical system of claim 1 , further including a high-pass filter disposed at an output side of the downconverter.

3. The optical system of claim 1 , further including a low-pass filter disposed at an input side of the downconverter.

4. The optical system of claim 1 , further including a reflector, the wavelength-selective optical filter and a measurement subject each being disposed between the reflector and the optical sensor along an optical path.

5. The optical system of claim 1 , further including a light source and a reflector, wherein the wavelength-selective optical filter and a measurement subject are each disposed between the light source and the reflector along an optical path.

6. The optical system of claim 1 , further including a light source, wherein the wavelength-selective optical filter and a measurement subject are each disposed between the light source and the optical sensor along an optical path.

7. The optical system of claim 1 , wherein the wavelength-selective optical filter is disposed between the optical sensor and a measurement subject along an optical path.

8. The optical system of claim 1 , wherein a measurement subject is disposed between the wavelength-selective optical filter and the optical sensor along an optical path.

9. An optical device, comprising:

an optical sensor;

a plurality of photosensitive pixels disposed on the optical sensor;

a wavelength-selective optical filter in optical communication with the photosensitive pixels;

a first plurality of spatially-variant areas disposed in the optical filter;

a second plurality of spatially-variant areas disposed in the optical filter; and

a third plurality of spatially-variant areas disposed in the optical filter,

wherein the wavelength-selective optical filter comprises first and second filter sheets, the first filter sheet defining therein at least one first written region and at least one first non-written region, the second filter sheet defining therein at least one second written region and at least one second non-written region, wherein:

the first plurality of spatially-variant areas comprises an area of the at least one first written region overlapping with an area of the at least one second non-written region;

the second plurality of spatially-variant areas comprises an area of the at least one first non-written region overlapping with an area of the at least one second written region; and

the third plurality of spatially-variant areas comprises an area of the at least one first written region overlapping with an area of the at least one second written region, and

wherein at least one area of the first, second or third pluralities of spatially-variant areas includes a downconverter.

10. The optical device of claim 9 , further including a high-pass filter disposed at an output side of the downconverter.

11. The optical device of claim 9 , further including a low-pass filter disposed at an input side of the downconverter.

12. The optical device of claim 9 , wherein the wavelength-selective optical filter includes a reference area.

13. The optical device of claim 9 , wherein the wavelength-selective optical filter is flexible.

14. The optical device of claim 9 , wherein a size of at least one area of the first plurality of spatially-variant areas is different from a size of at least one area of the second plurality of spatially-variant areas.

15. An optical device, comprising:

a wavelength-selective optical filter, the filter including:

a first plurality of spatially-variant areas disposed in the optical filter, at least one area of the first plurality of spatially-variant areas including a downconverter; and

a second plurality of spatially-variant areas disposed in the optical filter; and

a third plurality of spatially-variant areas disposed in the optical filter,

wherein the wavelength-selective optical filter comprises first and second filter sheets, the first filter sheet defining therein at least one first written region and at least one first non-written region, the second filter sheet defining therein at least one second written region and at least one second non-written region, and wherein:

the first plurality of spatially-variant areas comprises an area of the at least one first written region overlapping with an area of the at least one second non-written region;

the second plurality of spatially-variant areas comprises an area of the at least one first non-written region overlapping with an area of the at least one second written region; and

the third plurality of spatially-variant areas comprises an area of the at least one first written region overlapping with an area of the at least one second written region.