A novel plane mirror interferometer without using corner cube reflectors

Abstract

The conception and properties will be introduced of an interferometer that exclusively uses plane mirrors as reflectors; thus, these interferometers correspond well to the original Michelson interferometer. First, the relationship between the interference conditions and the detection with photodiodes will be discussed using the example of known interferometers as well as reasons given for primarily using corner cube reflectors in these devices. Next, the conceptual design of the plane mirror interferometer will be presented. This type of interferometer possesses new properties which are significant for metrological and technical applications. Only one measuring beam exists between the polarizing beam splitter and the measuring mirror and this beam alone represents the Abbe axis. This property allows the significant reduction of the Abbe error. The interferometer is able to tolerate tilting on the order of about 1′. This ensures the orthogonality between the measuring beam and the measuring mirror during the measurement. This property can be used in three-dimensional measurements to erect the three measuring beams as a x–y–z Cartesian coordinate system on the basis of three orthogonal mirrors. The plane-mirror interferometer also allows non-contact measurements of planar and curved surfaces, e.g. silicon wafers.

Influences of misalignments on circular path measurement based on dual-beam plane mirror interferometer

“…The DPMI for circular path measurement of the NC machine tool uses the plane mirror as measured target mirror, which can allow longitudinal (Measurement beam direction) and lateral (orthogonal direction with the measurement beam) displacements of the mirror during the measurement [13]. Therefore, the misalignment of the plane mirror (Orthogonal error of the plane mirror and measurement beam) will generate an error in the lateral displacement similar to the longitudinal displacement.…”

“…EX x4 = 0.0079x + 0.0003 (13) EX y3 = 0.0248y − 0.0030 (14) EX y4 = 0.0062y + 0.0003 (15) EX x3, EX x4 mean the longitudinal errors of the X-measurement under sate 3 and 4 respectively; EX y3, EX y4 mean the lateral errors of the X-measurement under sate 3 and 4 respectively; x, y mean the linear displacements of X (the longitudinal) and Y (the lateral) motions respectively.…”

Limitations of precision length measurements based on interferometers

“…those equipped with plane mirrors and those equipped with corner cube reflectors -are needed for applications in nanopositioning and nanomeasuring engineering. Only plane mirror interferometers allow the taking of three-dimensional coordinate measurements [5,6]. Figure 3 shows the difference between a plane mirror interferometer of the state of the art (above) and the interferometer developed by our institute (below) [5,6].…”

“…Only plane mirror interferometers allow the taking of three-dimensional coordinate measurements [5,6]. Figure 3 shows the difference between a plane mirror interferometer of the state of the art (above) and the interferometer developed by our institute (below) [5,6]. The most advantage of our plane mirror interferometer is that it has only one measuring beam.…”

Dimensional metrology in the macroscopic range with sub-nanometre resolution

“…The NMM-1 developed at the Ilmenau University of Technology and manufactured by SIOS Meßtechnik GmbH is equipped with three single-beam homodyne plane-mirror miniature interferometers for the measurement of the displacement of a movable corner mirror. [4][5][6] The object being measured is placed on the corner mirror, which is positioned by a three-axis drive system. The plane-mirror miniature interferometers and the probing system are fixed on a metrology frame made of Zerodur Ò .…”