Patent ID: 9046412
Filing Date: 2015-06-02
Classification: G01B,G01J

Abstract:
1. An interferometer, comprising: path differencing optics and a detector, wherein: the path differencing optics comprise at least two reflecting elements and a beamsplitter, the beamsplitter is arranged to divide an input beam into first and second beams respectively traversing first and second paths towards the detector, the first and second beams are respectively directed to first and second reflecting elements, the first reflecting element is arranged to direct the first beam to the second reflecting element, the second reflecting element is arranged to direct the first beam to the beamsplitter and on towards the detector, the second reflecting element is arranged to direct the second beam to the first reflecting element, the first reflecting element is arranged to direct the second beam to the beamsplitter and on towards the detector, the first and second paths having an optical path difference; and the detector is arranged to detect a pattern produced by interference of the first and second beams, and wherein the first and second reflecting elements are concavely curved to focus the first and second beams onto the detector; and the path differencing optics are arranged such that the first and second beams as they leave the beamsplitter for the detector are offset with respect to each other such that there is a shear angle between the beams.