Optical achromatic interferometer of the trilateral phase shift type.

摘要

In the interferometer proposed, an input lens defines a reference plane (PC), optically conjugate with the plane in which the wave front of a light beam is analysed. A bidimensional mesh grating (GR) is placed in this reference plane (PC), perpendicularly to the beam. The various partial beams due to the various diffraction orders are focused jointly by a first lens (L1) in an intermediate focal plane (PF), in the vicinity of which a mask (M) selects from these partial beams those which result from at least three different diffraction orders. A second lens (L2) brings the selected partial beams to a plane (PO), called the zero-sensitivity plane, which is conjugate with the plane of the grating. The interference image is observed in a working plane (PA) located at a chosen distance (d) from the zero-sensitivity plane.