Spectroferometers and methods of use are provided. The spectroferometers includes an enclosure, one or more interferometer beam-splitting elements, and one or more spectrometer beam-dispersing elements. The one or more interferometer beam-splitting elements and the one or more spectrometer beam-dispersing elements are housed in the enclosure, share one or more radiation sensitive elements, which are arranged to generate a signal in response to incident electromagnetic radiation, and each generate one or more optical outputs. The one or more optical outputs are arranged such that respective optical axes intersect substantially in a plane of the one or more radiation sensitive elements.

Disclosed is an optical sensor, including an external cavity laser configured to output sensing light and reference light; and a photodetector configured to detect a beating signal by an interference of the sensing light and the reference light output from the external cavity laser, in which the external cavity laser includes a reflecting filter including a sensing grating, to which a sensing object is attachable, and a reference grating, which is disposed on the same plane as that of the sensing grating, and outputs sensing light reflected from the sensing grating and reference light reflected from the reference grating. Accordingly, the optical sensor does not require a high-resolution spectroscope and has improved resolution and sensitivity.

The present invention provides a concave diffraction grating capable of improved diffraction efficiency by suppressing spherical aberration. The concave diffraction grating is a concave diffraction grating 2 for dispersing and focusing light and comprises sawtooth grating grooves 21 on a concave substrate 24, with the sawtooth grating grooves 21 being unequally spaced. The concave diffraction grating 2 for dispersing and focusing light is formed by preparing a planar diffraction grating with a sawtooth shape which is formed on a planar substrate by photo-lithography and etching or machining and which forms unequally spaced grating grooves 21, deforming and mounting the planar diffraction grating along a fixed convex substrate to obtain a mold of a concave diffraction grating, and transferring the mold of the concave diffraction grating to the surface of a metal or a resin.

Easy and accurate mating of a groove interval of a groove pattern of a diffraction grating with a position on a convex fixing substrate is enabled. For this purpose, a concave diffraction grating is fabricated by: transferring a groove pattern formed on a plane diffraction grating and having unequal groove intervals onto a metal thin film; forming a first alignment mark on a convex surface of a fixing substrate having the convex surface to fix the metal thin film; mating a second alignment mark formed on an adhesive surface of the metal thin film with the first alignment mark to perform alignment; bonding the adhesive surface of the metal thin film and the convex surface of the fixing substrate to each other to fabricate a master; and transferring a groove pattern of a metal thin film of the master.

A CubeSat compatible spectrometer including a slit having a first length and first width; a diffraction grating; and a two dimensional focal plane array electromagnetically coupled to the diffraction grating. The 2D focal plane array includes an array of pixels including a plurality of sets of pixels. Diffraction of electromagnetic radiation transmitted through the slit by the diffraction grating forms a plurality of beams, each of the beams comprising a different one of the bands of the wavelengths in the electromagnetic radiation, and each of the beams transmitted onto a different one of the sets of the pixels.

A spectral resolution enhancement device including a preliminary dispersion unit, a two-grating angular dispersion amplification unit, and a detection unit is provided. The preliminary dispersion unit is configured to receive collimated incident light and emits light of different wavelengths in the incident light at different angles. The two-grating angular dispersion amplification unit is configured to diffract the light of different wavelengths and emitted from the preliminary dispersion unit multiple times, such that angular dispersion the light of different wavelengths is enhanced, and emergent angle deviations between the light of different wavelengths are increased. The detection unit is configured to detect light of different wavelengths and emitted from the two-grating angular dispersion amplification unit. Since the emergent angle deviations of light of different wavelengths are increased, resolution of the detection unit for the light of different wavelengths is increased.

A spectral resolution enhancement device including a preliminary dispersion unit, a two-grating angular dispersion amplification unit, and a detection unit is provided. The preliminary dispersion unit is configured to receive collimated incident light and emits light of different wavelengths in the incident light at different angles. The two-grating angular dispersion amplification unit is configured to diffract the light of different wavelengths and emitted from the preliminary dispersion unit multiple times, such that angular dispersion the light of different wavelengths is enhanced, and emergent angle deviations between the light of different wavelengths are increased. The detection unit is configured to detect light of different wavelengths and emitted from the two-grating angular dispersion amplification unit. Since the emergent angle deviations of light of different wavelengths are increased, resolution of the detection unit for the light of different wavelengths is increased.

The present invention provides a concave diffraction grating capable of improved diffraction efficiency by suppressing spherical aberration. The concave diffraction grating is a concave diffraction grating 2 for dispersing and focusing light and comprises sawtooth grating grooves 21 on a concave substrate 24, with the sawtooth grating grooves 21 being unequally spaced. The concave diffraction grating 2 for dispersing and focusing light is formed by preparing a planar diffraction grating with a sawtooth shape which is formed on a planar substrate by photo-lithography and etching or machining and which forms unequally spaced grating grooves 21, deforming and mounting the planar diffraction grating along a fixed convex substrate to obtain a mold of a concave diffraction grating, and transferring the mold of the concave diffraction grating to the surface of a metal or a resin.

An irradiation region 21 of a diffraction grating 2 includes a first irradiation region (21A) and a second irradiation region (21B). In the diffraction grating 2, a blaze wavelength of a groove 22 of the first irradiation region (21A) is different from a blaze wavelength of a groove 23 of the second irradiation region (21B). That is, the first irradiation region (21A) and the second irradiation region (21B) have different relationships between a wavelength of light to be spectrally dispersed and a diffraction efficiency. Therefore, in a spectral device, light on a short wavelength side of light reflected by the second irradiation region (21B) of the diffraction grating 2 is not diffracted and is not received by a detector. Then, in a spectral device 1, aberration on the short wavelength side is corrected. In this way, in the diffraction grating 2, an aberration can be corrected with a simple structure in which the grooves (22, 23) are formed such that the blaze wavelengths in the first irradiation region (21A) and the second irradiation region (21B) are different from each other.

Easy and accurate mating of a groove interval of a groove pattern of a diffraction grating with a position on a convex fixing substrate is enabled. For this purpose, a concave diffraction grating is fabricated by: transferring a groove pattern formed on a plane diffraction grating and having unequal groove intervals onto a metal thin film; forming a first alignment mark on a convex surface of a fixing substrate having the convex surface to fix the metal thin film; mating a second alignment mark formed on an adhesive surface of the metal thin film with the first alignment mark to perform alignment; bonding the adhesive surface of the metal thin film and the convex surface of the fixing substrate to each other to fabricate a master; and transferring a groove pattern of a metal thin film of the master.