Interferometer spectrometer having means for varying the optical path length while maintaining alignment
First Claim
1. An interferometer comprising a beam splitter for splitting an incident radiation beam into two sub-beams following first and second separate paths, first and second fixed mirrors terminating the first and second paths and serving to reflect the sub-beam back to the beam splitter, the beam splitter being further arranged to re-combine the sub-beams, at least one of the first and second paths including path length variation means;
- characterized in that a third fixed mirror is arranged parallel to the beam splitter in the first path to direct radiation onto the first mirror, the first mirror being arranged to lie in a plane parallel to that containing the second mirror, wherein the first mirror lies in the same plane as that of the second mirror.
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Accused Products
Abstract
An interferometer which may be used in a Fourier transform infra red spectrometer comprises a beam splitter (10), first and second fixed mirrors (18,26), path length variation means (20), and a folding mirror (16). The optical components are mounted on a casting (8) such that the beam splitter (10) and folding mirror (16) are arranged parallel to each other and the fixed mirrors (18,26) are attached to a single face of the casting in the same plane. The path length variation means (20) comprises two parallel opposed mirrors (22,24) which are rotatable to vary the length of the optical path between the beam splitter (10) and the fixed mirror (26).
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Citations
8 Claims
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1. An interferometer comprising a beam splitter for splitting an incident radiation beam into two sub-beams following first and second separate paths, first and second fixed mirrors terminating the first and second paths and serving to reflect the sub-beam back to the beam splitter, the beam splitter being further arranged to re-combine the sub-beams, at least one of the first and second paths including path length variation means;
- characterized in that a third fixed mirror is arranged parallel to the beam splitter in the first path to direct radiation onto the first mirror, the first mirror being arranged to lie in a plane parallel to that containing the second mirror, wherein the first mirror lies in the same plane as that of the second mirror.
- View Dependent Claims (2, 3, 4, 5, 7, 8)
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6. An interferometer comprise a beam splitter for splitting an incident radiation beam into two sub-beams following first and second separate paths, first and second fixed mirrors terminating the first and second paths and serving to reflect the sub-beam back to the beam splitter, the beam splitter being further arranged to re-combine the sub-beams, at least one of the first and second paths including path length variation means;
- characterized in that a third fixed mirror is arranged parallel to the beam splitter in the first path to direct radiation onto the first mirror, the first mirror being arranged to lie in a plane parallel to that containing the second mirror, further comprising mirror mounting means comprising at least one finger urged against the mirror at a position adjacent to its fixed end and screw means adjacent to the free end of the finger serving to adjustably deflect the finger.
Specification