A spectral imaging device (12) includes an image sensor (28), a tunable light source (14), an optical assembly (17), and a control system (30). The optical assembly (17) includes a first refractive element (24A) and a second refractive element (24B) that are spaced apart from one another by a first separation distance. The refractive elements (24A) (24B) have an element optical thickness and a Fourier space component of the optical frequency dependent transmittance function. Further, the element optical thickness of each refractive element (24A) (24B) and the first separation distance are set such that the Fourier space components of the optical frequency dependent transmittance function of each refractive element (24A) (24B) fall outside a Fourier space measurement passband.

Gas analyzer or gas analysis method, in which beams of at least two different radiation sources are coupled into a Herriott cell containing a measurement gas and, after being reflected multiple times, are coupled out therefrom and detected, wherein the beams are aligned such that they strike mirrors in point patterns which extend along ellipses, where the different ellipses lie inside one another and have two shared vertices (co-vertices) on a shared axis of symmetry, whereas the other co-vertices (or vertices) do not coincide, the beams of at least two of the different radiation sources are coupled into the Herriott cell at differing points of the associated point pattern and/or are coupled into the Herriott cell such that they pass through the associated point patterns along the ellipses in opposite directions, and where all beams are coupled out at the point of one of the shared vertices.

A multi-angle imager (10) comprises an imaging array (Mij) configured to receive light beams (Li) via one or more entrance pupils (A1) according to distinct fields of view (Vi) of an object (P0) along each of multiple entry angles (αi). The imaging array (Mij) comprises multiple imaging branches (M1j, M2j) configured to form respective optical paths for the light beams (L1, L2) through the imager (10) for imaging respective subsections (S1, S2) of the object (P0). Each imaging branch (M1j) comprises a distinct set of optical elements (M11, M21) configured to receive the respective light beam (L1) along the respective entry angle (α1) and redirect the respective light beam (L1) towards the imaging plane (P1). The light beams (L1, L2) from each of the multiple imaging branches (M1j, M2j) are redirected to travel in a common direction (y) between the imaging array (Mij) and the imaging plane (P1).

A spectroscopic system may include: a probe having a probe tip and an optical coupler, the optical coupler including an emitting fiber group and first and second receiving fiber groups, each fiber group having a first end and a second end, wherein the first ends of the fiber groups are formed into a bundle and optically exposed through the probe tip; a light source optically coupled to the second end of the emitting fiber group, the light source emitting light in at least a first waveband and a second waveband, the second waveband being different from the first waveband; a first spectrometer optically coupled to the second end of the first receiving fiber group and configured to process light in the first waveband; and a second spectrometer optically coupled to the second end of the second receiving fiber group and configured to process light in the second waveband.

A non-contact multispectral measurement device for measuring reflectance properties of a surface of interest may include a multispectral measurement system, a position measurement system for measuring position values of the multispectral measurement system relative to the surface of interest, and means to correct multispectral values from the multispectral measurement system based on detected position values from the position measurement system. In some embodiments the multispectral measurement system is configured with a retro-reflection measurement geometry, where the illumination light path and observation light path are inclined with respect to a surface normal of the surface of interest to reduce detection of gloss or surface reflections while obtaining multispectral values. The position measurement system may be selected from the group consisting of: a pattern projector and a camera, a camera autofocus system, a stereo vision system, a laser range finder, and a time of flight distance sensor.

Transdermal optical sensing systems and methods of use are described. The systems include a main body, an internal reflection element arranged within the main body, with an internal reflection element surface exposed for contact with an epidermis, an optical source configured to project light into the internal reflection element, an optical detector arranged to detect reflected light that reflects internally within the internal reflection element from the internal reflection element surface, a controller configured to measure the light at the optical detector to determine the presence of one or more compounds within the epidermis, and a retention member attached to the main body, the retention member configured to wrap about a wrist of a patient.

An optical device may include a dispersion element. The optical device may include a reflective optic to reflect an optical beam with a fixed offset perpendicular to a dispersion direction of the dispersion element and with a negative offset in the dispersion direction of the dispersion element. The reflective optic may be aligned to the dispersion element to offset an optical beam with respect to the dispersion element and to cause the optical beam to pass through the dispersion element on a plurality of passes, offsetting the optical beam on each of the plurality of passes.

Provided is an optical element including: a main body which is formed of a medium capable of transmitting first light and second light having a wavelength longer than that of the first light, in which the main body includes an incident region into which the first light and the second light are incident, in which a gap which is inclined with respect to the incident region and in which a medium having a refractive index with respect to the first light and the second light lower than that of the main body is disposed is provided inside the main body, and in which a gap width from an interface bordering the main body and the gap is larger than a penetration length of an evanescent wave of the first light at the interface and is smaller than a penetration length of an evanescent wave of the second light at the interface.

Systems and methods are provided for filtering coherent infrared light from a thermal background for protection of infrared (IR) imaging arrays and detection systems. A Michelson interferometer is used for coherent light filtering. In an implementation, a system includes a fixed mirror, a beam splitter, and a moving mirror which can be controlled translationally, as well as tip/tilt. The Michelson interferometer may be used as an imaging system. For imaging applications, a system may comprise a tunable array of micro-electromechanical systems (MEMS) mirrors. A mid-wave IR interferometer with electronic feedback and MEMS mirror array is provided.

An optical system to divide a light flux from an object plane includes a first curved-surface mirror, and second, third, and fourth reflecting portions. The second reflecting portion divides and reflects light flux from the first curved-surface mirror to respective different positions on the first curved-surface mirror as first light fluxes. The third reflecting portion reflects, as third light fluxes, the first light fluxes. The fourth reflecting portion reflects the third light fluxes from the third reflecting portion. A number of reflective surfaces of each of the third and fourth reflecting portions on which the first and third light fluxes are incident is the same as a division number in the dividing of the light flux into the second light fluxes. The first and third light fluxes are reflected by the respective third and fourth reflecting portions to be image-formed so that divided images of the object plane are formed.