A hyperspectral optical element for monolithic detectors is provided. In one embodiment, for example a hyperspectral optical element includes a faceplate layer adapted to be mounted on top of a monolithic detector. The faceplate layer comprises a reflective inner surface. A notched layer includes a plurality of notched surfaces and is mounted to the faceplate layer. The notched surfaces oppose the reflective inner surface of the faceplate and define a plurality of variable depth cavities between the reflective inner surface of the faceplate layer and the plurality of notched surfaces of the notched layer. The faceplate layer and the notched layer are substantially transparent to a received signal and the plurality of variable depth cavities provides resonant cavities for one or more wavelengths of the received signal.

An optical assembly is disclosed including two laterally variable bandpass optical filters stacked at a fixed distance from each other, so that the upstream filter functions as a spatial filter for the downstream filter. The lateral displacement may cause a suppression of the oblique beam when transmission passbands at impinging locations of the oblique beam onto the upstream and downstream filters do not overlap. A photodetector array may be disposed downstream of the downstream filter. The optical assembly may be coupled via a variety of optical conduits or optical fibers for spectroscopic measurements of a flowing sample.

A spectral camera for producing a spectral output is disclosed. The spectral camera has an objective lens for producing an image, an optical duplicator, an array of filters, and a sensor array arranged to detect the filtered image copies simultaneously on different parts of the sensor array. Further, a field stop defines an outline of the image copies projected on the sensor array. The filters are integrated on the sensor array, which has a planar structure without perpendicular physical barriers for preventing cross talk between each of the adjacent optical channels. The field stop enables adjacent image copies to fit together without gaps for such barriers. The integrated filters mean there is no parasitic cavity causing crosstalk between the adjacent image copies. This means there is no longer a need for barriers between adjacent projected image copies, and thus sensor area can be better utilized.

The invention relates to a multi-pass etalon-based optical filter in which input light once reflected from the etalon is returned back to the etalon for a second reflection to enhance etalon contrast. The external mirror may be tilted relative to the etalon so that two planes of incidence are orthogonal. The multi-pass etalon-based optical filter may be used to clean scattered light from an excitation wavelength in Raman and Brillouin spectroscopy.

A spectral imager includes a filter array, a pixel array, and a lenslet array therebetween. The filter array includes a plurality of filter regions. The lenslet array includes a plurality of lenslets each configured to form a respective image of the filter array on a respective one of a plurality of regions of the pixel array. The spectral imager may also include a fore-optic lens, the filter array being located between the lenslet array and the fore-optic lens. The spectral imager may also include a fore-optic lens, the filter array being located between the lenslet array and the fore-optic lens. Each of the plurality of filter regions is configured to selectively transmit radiation based on wavelength and/or polarization.

Devices, methods and systems for generating wideband, high-fidelity arbitrary radio frequency (RF) passband signals are described. A voltage tunable optical filter for arbitrary RF passband signal generation includes a first input configured to receive a broadband optical pulse train, a second input configured to receive a first control voltage representative of an amplitude signal, an electrooptic modulator to receive the broadband optical pulse train and the first control voltage, to modulate the broadband optical pulse train in accordance with the amplitude signal, and to produce two complementary optical outputs that form two arms of an interferometer, an optical delay component to impart an optical path difference into one of the complementary outputs of the electrooptic modulator, and a combiner or a splitter to receive two complementary optical outputs of the electrooptic modulator after impartation of the optical path difference and to produce an output interference pattern of fringes.

A spectroscopic sensor includes a wiring substrate having a main surface, a light detector disposed on the main surface of the wiring substrate, a Fabry-Perot interference filter, a spacer which is provided on the main surface of the wiring substrate and supports the Fabry-Perot interference filter so that the Fabry-Perot interference filter and the light detector are separated from each other, and a stein connected to a ground potential. A second current path which has a smaller electric resistance than that of an arbitrary first current path which extends from the Fabry-Perot interference filter to the light detector via the spacer and the wiring substrate is formed between the Fabry-Perot interference filter and the stein.

A spectroscopic unit includes a housing, a light incident portion provided in the housing, a Fabry-Perot interference filter arranged in the housing and having a first mirror and a second mirror, a distance between the first mirror and the second mirror being variable. The light incident portion includes an aperture portion in which an aperture is formed and a band pass filter arranged between the aperture and the Fabry-Perot interference filter. The aperture portion is configured so that a value obtained by dividing a length of the aperture in a facing direction of the first mirror and the second mirror by a width of the aperture in a direction perpendicular to the facing direction is equal to or more than 0.5 and the entirety of light passing through the aperture is incident on the band pass filter.

A light detection device includes a Fabry-Perot interference filter, a light detector, a spacer that has a placement surface on which a portion outside a light transmission region in a bottom surface of the interference filter is placed, and an adhesive member that adheres the interference filter and the spacer to each other. Elastic modulus of the adhesive member is smaller than elastic modulus of the spacer. At least a part of a lateral surface of the interference filter is located on the placement surface such that a part of the placement surface of the spacer is disposed outside the lateral surface. The adhesive member is disposed in a corner portion formed by the lateral surface of the interference filter and the part of the placement surface of the spacer and contacts each of the lateral surface and the part of the placement surface.

The teachings of the present disclosure enable a reduction of the refractive index of a material by incorporating an additive selected from air, vacuum, or an inert gas in the material to turn the material into a material foam that is suitable for use in optical systems. A material foam in accordance with the present disclosure is characterized by a porosity that reduces its refractive index from that of the same material as found in nature. The higher porosity also decreases the density of the material from that of the same material as found in nature. Material foams in accordance with the present disclosure are suitable for use in the low-refractive-index layers of a Bragg mirror.