Patent ID: 6469790
Filing Date: 2002-10-22
Classification: G01J

Abstract:
A spectrometer, comprising:a source of a primary beam of radiant energy; a beamsplitter, fixed relative to the primary beam, the beamsplitter dividing the primary beam into at least a first energy beam and a second energy beam, the first energy beam traversing at least a first optical path, the second energy beam traversing at least a second optical path, the beamsplitter containing an uncoated portion through which at least one optical path passes; at least a first reflector, the first reflector positioned so as to reflect the first energy beam back to at least the beamsplitter; at least a second reflector, the second reflector being moveable with respect to the primary beam and positioned to receive the second energy beam for at least a first reflection, a second reflection, a third reflection, and a fourth reflection; at least a first retroreflector, the first retroreflector positioned to receive the first reflection of the second energy beam from at least the second reflector, the first retroreflector returning the second energy beam to at least the second reflector for the second reflection; at least a third reflector, the third reflector positioned so as to receive the second reflection of second energy beam from at least the second reflector and to return the second energy beam to at least the second reflector for the third reflection of the second energy beam, at least a first portion of the second optical path that is traversed by the second energy beam from the second reflector to the third reflector being antiparallel to at least a second portion of the second optical path traversed by the second energy beam from at least the third reflector to the second reflector; the second reflector returning the third reflection of the second energy beam to at least the first retroreflector; the first retroreflector returning the second energy beam to at least the second reflector for the fourth reflection of the second energy beam; the second reflector returning the second energy beam to the beamsplitter, the returned second energy beam being in reverse order and in an inverted state to make the returned second energy beam complementary with at least the portion of the second energy beam traversing a path from the beamsplitter to at least the second reflector; and the beamsplitter combining at least portions of the first and second energy beams and transmitting the combined portions of the first and second energy beams to a detector.