System for optical imaging comprising matched spectral filters
Systems, methods and devices are for optical imaging are described. A system includes a light source and a light detection unit. The light source includes a light-emitting device and a first spectral filter opposite the light emitting device. The first spectral filter includes at least one dielectric filter and has a first angular dependence of a transmission passband. The light source further includes at least one reflector adjacent side surfaces of the light emitting device. The light detection unit includes an optical sensor and a second spectral filter opposite the optical sensor. The second spatial filter has a second angular dependence of a transmission passband that is matched to the first angular dependence.
1. A system comprising:
a light source comprising:
a light-emitting device,
a first spectral filter opposite the light emitting device, the first spectral filter comprising at least one dielectric filter and having a first angular dependence of a transmission passband, and
at least one reflector adjacent side surfaces of the light emitting device; and
a light detection unit comprising:
an optical sensor, and
a second spectral filter opposite the optical sensor, the second spatial filter having a second angular dependence of a transmission passband that is matched to the first angular dependence.
2. The system of claim 1 , wherein the first spectral filter and the second spectral filter have substantially identical transmission passbands, and the first angular dependence and the second angular dependence are substantially identical.
3. The system of claim 1 , wherein at least one of the first spectral filter and the second spectral filter has a narrow transmission passband having a full width at half maximum (FWHM) of 50 nm or smaller.
4. The system of claim 1 , wherein the light source is adjacent the light detection unit.
5. The system of claim 1 , wherein the second spectral filter comprises at least one dielectric filter.
6. The system of claim 1 , wherein at least one of the first spectral filter and the second spectral filter comprises at least one of: at least one photonic crystal, at least one diffractive optical element, at least one metasurface filter, at least one plasmonic filter and at least one nano-resonator filter.
7. The system of claim 1 , wherein at least one of the first spectral filter and the second spectral filter has one of a single transmission passband and a dual transmission passband.
8. The system of claim 1 , wherein the light-emitting device comprises at least one light-emitting diode.
9. The system of claim 1 , wherein the system is one of an optical authentication system and a machine vision system.
10. A lighting device for optical imaging, the lighting device comprising:
a light source;
a first spectral filter opposite the light source, the first spectral filter comprising at least one dielectric filter and having a first angular dependence of a transmission passband matched to a second angular dependence of a transmission passband of a second spectral filter of a light detection unit; and
at least one reflector adjacent side surfaces of the light emitting device.
11. The device of claim 10 , wherein the device is for one of optical authentication and machine vision.
12. The device of claim 10 , wherein the first spectral filter comprises at least one of: at least one photonic crystal, at least one diffractive optical element, at least one metasurface filter, at least one plasmonic filter and at least one nano-resonator filter.
13. The device of claim 10 , wherein the first spectral filter has one of a single transmission passband and a dual transmission passband.
14. The device of claim 10 , wherein the light source comprises at least one light-emitting diode.
15. The device of claim 10 , wherein the first spectral filter has a narrow transmission passband having a full width at half maximum (FWHM) of 50 nm or smaller.
16. The device of claim 10 , further comprising a substrate on which the light source is disposed, the substrate having regions adjacent the light source that are at least partially covered with a reflective coating.
17. The device of claim 16 , further comprising a transparent filler material filling empty space between the reflective coating, the light source, the at least one reflector and the first spectral filter.
18. The device of claim 10 , further comprising a transparent carrier adjacent the first spectral filter.
19. A method of manufacturing a lighting device for optical imaging, the method comprising:
providing a light source;
providing a first spectral filter, the first spectral filter having a first angular dependence of a transmission passband and comprising at least one dielectric filter;
matching the first angular dependence to a second angular dependence of a transmission passband of second spectral filter for a light detection unit;
partially encasing the light source in a package comprising reflective elements; and
coupling the first spectral filter to the package.
20. The method of claim 19 , further comprising filling empty spaces in the package with a transparent filler material.