Optical filter and sensor system
DC CAFCFirst Claim
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1. An optical filter comprising:
- a filter stack comprising;
a plurality of hydrogenated silicon layers, wherein the plurality of hydrogenated silicon layers have a refractive index of greater than 3 over a wavelength range of 800 nm to 1100 nm and an extinction coefficient of less than 0.0005 over the wavelength range of 800 nm to 1100 nm; and
a plurality of lower-refractive-index layers, wherein the plurality of lower-refractive-index layers each have a refractive index of less than 3 over the wavelength range of 800 nm to 1100 nm, and wherein the plurality of lower-refractive-index layers are stacked in alternation with the plurality of hydrogenated silicon layers;
wherein the optical filter has a passband at least partially overlapping with the wavelength range of 800 nm to 1100 nm,wherein the passband has a center wavelength that shifts by less than 20 nm in magnitude with a change in an incidence angle between 0°
to 30°
, thereby providing the optical filter with a wide incidence-angle acceptance range.
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Abstract
An optical filter having a passband at least partially overlapping with a wavelength range of 800 nm to 1100 nm is provided. The optical filter includes a filter stack formed of hydrogenated silicon layers and lower-refractive index layers stacked in alternation. The hydrogenated silicon layers each have a refractive index of greater than 3 over the wavelength range of 800 nm to 1100 nm and an extinction coefficient of less than 0.0005 over the wavelength range of 800 nm to 1100 nm.
35 Citations
23 Claims
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1. An optical filter comprising:
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a filter stack comprising; a plurality of hydrogenated silicon layers, wherein the plurality of hydrogenated silicon layers have a refractive index of greater than 3 over a wavelength range of 800 nm to 1100 nm and an extinction coefficient of less than 0.0005 over the wavelength range of 800 nm to 1100 nm; and a plurality of lower-refractive-index layers, wherein the plurality of lower-refractive-index layers each have a refractive index of less than 3 over the wavelength range of 800 nm to 1100 nm, and wherein the plurality of lower-refractive-index layers are stacked in alternation with the plurality of hydrogenated silicon layers; wherein the optical filter has a passband at least partially overlapping with the wavelength range of 800 nm to 1100 nm, wherein the passband has a center wavelength that shifts by less than 20 nm in magnitude with a change in an incidence angle between 0°
to 30°
, thereby providing the optical filter with a wide incidence-angle acceptance range. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A sensor system comprising:
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an optical filter, having a passband including an emission wavelength and at least partially overlapping with a wavelength range of 800 nm to 1100 nm, being disposed to receive emitted light and transmit the emitted light, wherein the emitted light is, emitted from a light source, at the emission wavelength in the wavelength range of 800 nm to 1100 nm, and wherein the optical filter includes a filter stack including; a plurality of hydrogenated silicon layers, wherein the plurality of hydrogenated silicon layers each have a refractive index of greater than 3 over the wavelength range of 800 nm to 1100 nm and an extinction coefficient of less than 0.0005 over the wavelength range of 800 nm to 1100 nm; and a plurality of lower-refractive-index layers, wherein the plurality of lower-refractive-index layers each have a refractive index of less than 3 over the wavelength range of 800 nm to 1100 nm, and wherein the plurality of lower-refractive-index layers are stacked in alternation with the plurality of hydrogenated silicon layers, wherein a passband of the optical filter has a center wavelength that shifts by less than 20 nm in magnitude with a change in an incidence angle between 0°
to 30°
, thereby providing the optical filter with a wide incidence-angle acceptance range; anda sensor, disposed to receive the emitted light after transmission by the optical filter, for detecting the emitted light. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23)
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Specification