MULTIPLE BEAM SOURCE FOR A MULTI-BEAM INTERFEROMETER AND MULTI-BEAM INTERFEROMETER

摘要

A multi-beam interferometer, typically for use in Optical Coherence Tomography, comprising a multiple beam source (1), the source being arranged so as to provide, in use, a plurality of beams (101-105) of light for use in the interferometer, the source comprising: a light source (2) arranged to, in use, emit a beam of light (9); and a rattle plate (3) comprising a first reflective surface (4) and a second reflective surface (5) facing one another, the second reflective surface (5) being only partially reflective; in which the light source (2) and the rattle plate (3) are positioned relative to one another such that, in use, the beam of light (9) is incident on the rattle plate (3) such that the beam of light is repeatedly reflected along a beam path between the first and second reflective surfaces (4, 5), each successive and spaced-apart reflection off the partially reflective second reflective surface causing a portion of the light beam (9) to be transmitted through the second reflective surface (5) to form one of the beams of the plurality of beams (101-105); and in which between at least one successive pair of beams (104, 105) of the plurality of beams there is a decrease along the beam path in the level of reflectance due to the second reflective surface (5). Furthermore, the interferometer comprises a balance beam channel, comprising an optical path for a balance beam (105) and a detector (23) for the intensity of the balance beam in which, in use, the detected intensity of the balance beam is used to correct for laser amplitude variation, in which the balance beam has an intensity as high or higher than any other of the plurality of beams (101-104).