Patent ID: 7440108
Filing Date: 2008-10-21
Classification: G01J

Abstract:
1. An imaging spectrometer comprising on a longitudinal axis of the spectrometer: (i) an input polariser for resolving light incident thereon into a single linear polarisation state, (ii) a first polarising beam splitter arranged to receive light passing through the input polariser, and arranged to resolve said light into equal magnitude orthogonally polarised rays, said rays being mutually spaced and having a path difference therebetween, (iii) at least one additional polarising beam splitter arranged to receive light passing through the first polarising beam splitter, (iv) an output polariser orientated such that its transmission axis is parallel to or perpendicular to the transmission axis of the input polariser for resolving the orthogonally polarised light rays having passed through the or each additional polarising beam splitter into the same or perpendicular polarisation state as light resolved by the first polariser, (v) focussing means, the first polarising beam splitter, the or each additional beam splitter and the focussing means being mutually spaced such that said mutually spaced rays are brought to coincidence whereby interference fringes are produced, and, (vi) a light sensitive detector arranged to detect said interference fringes, wherein one polarising beam splitter is mounted for movement perpendicular to said longitudinal axis of the spectrometer, the other polarising beam splitter(s) being rigidly mounted against movement.