Abstract: An imaging spectrometer is disclosed that comprises imaging means for dividing a received image into two or more spatially separated images and means for detecting each spectral image, and is characterized in that the imaging means comprises at least one polarizing beam splitter. The polarizing beam splitter may be a Wollaston prism. In one embodiment of the invention, the imaging means comprises image replication means to produce two or more spatially separated images, and one or more filter elements such as dichroic filters which act to alter the spectral characteristics of one or more of the spatially separated images. In a further embodiment of the invention the imaging means comprises one or more spectral replication means arranged in optical series, each spectral replication means comprising an optical retardation element and a polarizing beam splitter.

Abstract: The present invention relates to an imaging apparatus and comprises input and output polarisers, a first polarising beam splitter and at least one additional polarising beam splitter, a light sensitive detector and focussing means arranged on an axis. The input polariser resolves incident light into a single linear polarisation state. The first polarising beam splitter receives light from the input polarises, and resolves it into equal magnitude orthogonally polarised rays which are mutually spaced and have a path difference therebetween. The or each additional polarising beam splitter is arranged to receive light from the first polarising beam splitter. The transmission axis of the output polariser is parallel to or perpendicular to the transmission axis of the input polarises to resolve the orthogonally polarised light rays having past through the or each additional polarising beam splitter into the same or perpendicular polarisation state as light resolved by the, first polariser.