| 摘要 |
The present invention concerns an interferometer in which the input light beam is incident at a non-normal angle of incidence on a pair of reflective interfaces, wherein the front surface is partially reflective and the rear interface inclined at an angle relative to the front face so that the input beam is amplitude split into two spatially offset collimated beam propagating at an angle relative to one another. Lens means are provided for focussing the beams to create a pair of focal spots in the focal plane of said lens means so that the light reflected from a measurement plane in or very near to the focal plane is re-collimated by the same lens used to focus the beams. The light then propagates back through the input beam dividing optic and recombines to cause interference.
|
