Abstract: In some implementations, an optical interference filter includes a substrate; and a set of layers that are disposed on the substrate. The set of layers includes a first subset of layers, wherein the first subset of layers comprises an aluminum nitride (AlN) material; and a second subset of layers, wherein the second subset of layers comprises a hydrogenated silicon (Si:H) material.

Abstract: In some implementations, an optical interference filter includes a substrate; and a set of layers that are disposed on the substrate, wherein the set of layers includes: a first subset of layers; and a second subset of layers; wherein: each of the first subset of layers comprises an aluminum nitride (AlN) material, a stress of each of the first subset of layers is between ?1000 and 800 megapascals, the first subset of layers has a first refractive index with a first value, each of the second subset of layers comprises at least one other material, the second subset of layers has a second refractive index with a second value that is different than the first value, and the optical interference filter has an effective refractive index greater than or equal to 95% of a highest value of the first value and the second value.

Abstract: A zoned waveplate has a series of transversely stacked birefringent zones alternating with non-birefringent zones. The birefringent and non-birefringent zones are integrally formed upon an AR-coated face of a single substrate by patterning the AR coated face of the substrate with zero-order sub-wavelength form-birefringent gratings configured to have a target retardance. The layer structure of the AR coating is designed to provide the target birefringence in the patterned zones and the reflection suppression.

Abstract: In some implementations, an optical interference filter includes a substrate; and a set of layers that are disposed on the substrate. The set of layers includes a first subset of layers, wherein the first subset of layers comprises an aluminum nitride (AlN) material, and wherein a stress of the first subset of layers is between ?1000 and 800 megapascals; and a second subset of layers, wherein the second subset of layers comprises at least one other material.

Abstract: In some implementations, an optical interference filter includes a substrate; and a set of layers that are disposed on the substrate. The set of layers includes a first subset of layers, wherein the first subset of layers comprises an aluminum nitride (AlN) material; and a second subset of layers, wherein the second subset of layers comprises a hydrogenated silicon (Si:H) material.

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 mn to 1100 nm and an extinction coefficient of less than 0.0005 over the wavelength range of 800 nm to 1100 nm.

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.

Abstract: A dichroic prism beamsplitter may include a medium with a refractive index greater than approximately 1.0. The dichroic prism beamsplitter may include a plurality of layers sandwiched by the medium. The plurality of layers may include an equivalent structure including at least one layer with a refractive index that is less than a threshold refractive index for total internal reflection. The at least one layer may be associated with a thickness less than or equal to a threshold thickness associated with total internal reflection for a threshold wavelength. The at least one layer may cause total internal reflection for a first wavelength range that is less than or equal to the threshold wavelength and causes evanescent wave coupling for a second wavelength range that is greater than the threshold wavelength.

Abstract: An optical sensor assembly is provided in which a dark mirror coating is used to suppress stray light in the form of both unwanted reflections from non-optically active regions of the sensor assembly surface and unwanted transmission of light into the surface region of the sensor assembly. The sensor assembly includes an image sensor positioned in a substrate adjacent to substrate surface areas that are not optically active. A dark mirror coating covering those surface areas significantly reduces reflections from non-optically active surface regions and improves image sensor performance in terms of signal-to-noise ratio and reduction in the appearance of “ghost” images, in turn enhancing the accuracy and precision of the sensor. The dark mirror coating may in the alternative, or in addition, be positioned underneath an optical filter, depending on the structure, material, and requirements of a particular sensor assembly.

Abstract: An optical filter may include a substrate. The optical filter may include a set of alternating high refractive index layers and low refractive index layers disposed onto the substrate to polarization beam split incident light. The set of alternating high refractive index layers and low refractive index may layers may be disposed such that a first polarization of the incident light with a spectral range of less than approximately 800 nanometers (nm) is reflected by the optical filter and a second polarization of the incident light with a spectral range of greater than approximately 800 nm is passed through by the optical filter. The high refractive index layers may be hydrogenated silicon (Si:H). The low refractive index layers may be silicon dioxide (SiO2).

Abstract: A variable optical filter is disclosed including a bandpass filter and a blocking filter. The bandpass filter includes a stack of alternating first and second layers, and the blocking filter includes a stack of alternating third and fourth layers. The first, second and fourth materials each comprise different materials, so that a refractive index of the first material is smaller than a refractive index of the second material, which is smaller than a refractive index of the fourth material; while an absorption coefficient of the second material is smaller than an absorption coefficient of the fourth material. The materials can be selected to ensure high index contrast in the blocking filter and low optical losses in the bandpass filter. The first to fourth layers can be deposited directly on a photodetector array.

Abstract: A variable optical filter is disclosed including a bandpass filter and a blocking filter. The bandpass filter includes a stack of alternating first and second layers, and the blocking filter includes a stack of alternating third and fourth layers. The first, second and fourth materials each comprise different materials, so that a refractive index of the first material is smaller than a refractive index of the second material, which is smaller than a refractive index of the fourth material; while an absorption coefficient of the second material is smaller than an absorption coefficient of the fourth material. The materials can be selected to ensure high index contrast in the blocking filter and low optical losses in the bandpass filter. The first to fourth layers can be deposited directly on a photodetector array.

Abstract: A zoned waveplate has a series of transversely stacked birefringent zones alternating with non-birefringent zones. The birefringent and non-birefringent zones are integrally formed upon an AR-coated face of a single substrate by patterning the AR coated face of the substrate with zero-order sub-wavelength form-birefringent gratings configured to have a target retardance. The layer structure of the AR coating is designed to provide the target birefringence in the patterned zones and the reflection suppression.

Abstract: A zoned waveplate has a series of transversely stacked birefringent zones alternating with non-birefringent zones. The birefringent and non-birefringent zones are integrally formed upon an AR-coated face of a single substrate by patterning the AR coated face of the substrate with zero-order sub-wavelength form-birefringent gratings configured to have a target retardance. The layer structure of the AR coating is designed to provide the target birefringence in the patterned zones and the reflection suppression.

Abstract: A variable optical filter is disclosed including a bandpass filter and a blocking filter. The bandpass filter includes a stack of alternating first and second layers, and the blocking filter includes a stack of alternating third and fourth layers. The first, second and fourth materials each comprise different materials, so that a refractive index of the first material is smaller than a refractive index of the second material, which is smaller than a refractive index of the fourth material; while an absorption coefficient of the second material is smaller than an absorption coefficient of the fourth material. The materials can be selected to ensure high index contrast in the blocking filter and low optical losses in the bandpass filter. The first to fourth layers can be deposited directly on a photodetector array.

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.

Abstract: A variable optical filter is disclosed including a bandpass filter and a blocking filter. The bandpass filter includes a stack of alternating first and second layers, and the blocking filter includes a stack of alternating third and fourth layers. The first, second and fourth materials each comprise different materials, so that a refractive index of the first material is smaller than a refractive index of the second material, which is smaller than a refractive index of the fourth material; while an absorption coefficient of the second material is smaller than an absorption coefficient of the fourth material. The materials can be selected to ensure high index contrast in the blocking filter and low optical losses in the bandpass filter. The first to fourth layers can be deposited directly on a photodetector array.

Abstract: An optical sensor assembly is provided in which a dark mirror coating is used to suppress stray light in the form of both unwanted reflections from non-optically active regions of the sensor assembly surface and unwanted transmission of light into the surface region of the sensor assembly. The sensor assembly includes an image sensor positioned in a substrate adjacent to substrate surface areas that are not optically active. A dark mirror coating covering those surface areas significantly reduces reflections from non-optically active surface regions and improves image sensor performance in terms of signal-to-noise ratio and reduction in the appearance of “ghost” images, in turn enhancing the accuracy and precision of the sensor. The dark mirror coating may in the alternative, or in addition, be positioned underneath an optical filter, depending on the structure, material, and requirements of a particular sensor assembly.

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.

Abstract: A dichroic prism beamsplitter may include a medium with a refractive index greater than approximately 1.0. The dichroic prism beamsplitter may include a plurality of layers sandwiched by the medium. The plurality of layers may include an equivalent structure including at least one layer with a refractive index that is less than a threshold refractive index for total internal reflection. The at least one layer may be associated with a thickness less than or equal to a threshold thickness associated with total internal reflection for a threshold wavelength. The at least one layer may cause total internal reflection for a first wavelength range that is less than or equal to the threshold wavelength and causes evanescent wave coupling for a second wavelength range that is greater than the threshold wavelength.