A mirror unit 2 includes a mirror device 20 including a base 21 and a movable mirror 22, an optical function member 13, and a fixed mirror 16 that is disposed on a side opposite to the mirror device 20 with respect to the optical function member 13. The optical function member 13 is provided with a light transmitting portion 14 that constitutes a part of an optical path between the beam splitter unit 3 and the fixed mirror 16. The light transmitting portion 14 is a portion that corrects an optical path difference that occurs between an optical path between the beam splitter unit 3 and the movable mirror 22 and the optical path between the beam splitter unit 3 and the fixed mirror 16. The second surface 21b of the base 21 and the third surface 13a of the optical function member 13 are joined to each other.

Aspects of the disclosure relate to an integrated spectral unit including a micro-electro-mechanical systems (MEMS) interferometer fabricated within a first substrate and a light redirecting structure integrated on a second substrate, where the second substrate is coupled to the first substrate. The light redirecting structure includes at least one mirror for receiving an input light beam propagating in an out-of-plane direction with respect to the first substrate and redirecting the input light beam to an in-plane direction with respect to the first substrate towards the MEMS interferometer.

The present invention is directed to an Interferometer (100) comprising a source (110) of a primary energy beam (111), a first reflector (120) being provided static such that a first path length from the source (110) to the first reflector (120) is constant, a reflector (1) with an energy beam reflecting surface (20) being provided by an outer surface of a sonotrode (10), wherein the reflector (1) is provided to oscillate such that a second path length from the source (110) to the reflecting surface (20) is variable, a target (140), a means for splitting an energy beam (160) arranged such that it divides the primary beam (111) into a first energy beam (112) incident onto the first reflector (120), and a second energy beam (113) incident onto the reflector (1) adapted to oscillate, and a means for combining energy beams (170) arranged such that it combines a third energy beam (114) reflected from the first reflector (120) and a fourth energy beam (115) reflected from the reflector (1) adapted to oscillate incident onto the target (140). Further provided is an infrared Fourier transform spectrometer (200).

A typical configuration of the angle adjustment mechanism according to the present invention is provided with a parabolic mirror, a housing accommodating a parabolic mirror, a screw including a head arranged outside the housing and a shaft engaged with the parabolic mirror through a hole formed in the housing, and a base portion in contact with both the housing and the parabolic mirror. A force is applied to an engaging portion of the parabolic mirror in a direction approaching the housing and a force is applied to a portion of the parabolic mirror in contact with the base portion in a direction away from the housing. The angle of the parabolic mirror with respect to the housing changes in accordance with the change in the length of a portion where the shaft and the parabolic mirror engage.

Systems and methods according to exemplary embodiments of the present disclosure can be provided that can efficiently detect the amplitude and phase of a spectral modulation. Such exemplary scheme can be combined with self-interference fluorescence to facilitate a highly sensitive depth localization of self-interfering radiation generated within a sample. The exemplary system and method can facilitate a scan-free depth sensitivity within the focal depth range for microscopy, endoscopy and nanoscopy.

An apparatus for performing Raman spectral analysis of a sample is described, comprising a coherent light source, an first optical chain to direct the coherent light to impinge on the sample, a second optical chain to direct the scattered light onto a diffraction grating, and a third optical chain to direct the diffracted light onto detection array. The diffraction grating is a stairstep with a metalized surface, and a plurality of metalized stripes on a flat surface is disposed in a direction orthogonal to the long dimension of the stairsteps. The region between the flat surface and the stairstep is transparent. The zeroth-order fringe is selected by a slit and directed onto camera. The resultant interferogram is Fourier transformed to produce a representation of the Raman spectrum.

Novel monolithic cyclical reflective spatial heterodyne spectrometers (CRSHS) are presented. Monolithic CRSHS in accordance with the invention have a single frame wherein a flat mirror, roof mirror, and symmetric grating are affixed. The invention contains only fixed parts; the flat mirror, roof mirror, and symmetric grating do not move in relation to the frame. Compared to conventional CRSHS known in the art, the present invention enables much smaller and lighter CRSHS, requires less time and skill for maintenance, and is a better economic option. The disclosed invention may include fixed field-widening optical elements or a fiber-fed assembly.

An optical arrangement has a light source, which emits a light beam along a first optical axis. A first reflector is provided, and a second reflector reflects light reflected by the first reflector. The first reflector has a transverse offset from the first optical axis to reflect light along a second optical axis which has a parallel offset of two times the transverse offset of the first optical axis. The second reflector reflects the light beam back to the first reflector along a third optical axis having a parallel offset with a fixed amount in a fixed transverse direction in relation to the second optical axis. The light beam is reflected by the first reflector along a fourth optical axis which has a parallel offset in relation to the first optical axis with a fixed amount counter to the fixed transverse direction.

According to an aspect, there is provided a spectrometer comprising a first and second enclosed volumes. The second enclosed volume is formed by an absorption cell for containing a sample gas. The first enclosed volume of the spectrometer comprises an interferometer with a source of electromagnetic radiation, a first focusing mirror adapted to focus electromagnetic radiation received from the interferometer to the absorption cell, a second focusing mirror adapted to focus electromagnetic radiation received from the absorption cell and a detector adapted to detect electromagnetic radiation focused by the second focusing mirror. Moreover, the spectrometer comprises a main frame plate on which elements in the first enclosed volume are mounted and which is fixed to the absorption cell arranged on an opposing side of the main frame plate.

A photodetection device comprises: an image sensor that includes first pixels, second pixels, third pixels, and fourth pixels; an interference element that includes first incident regions and second incident regions; and an optical system that causes light in a first wavelength band to be incident on the first incident regions and causes light in a second wavelength band different from the first wavelength band to be incident on the second incident regions. The interference element causes first interference of part of the light in the first wavelength band incident on two first incident regions that are included in the first incident regions. The interference element also causes second interference of part of the light in the second wavelength band incident on two second incident regions.