Lateral shearing interferometer based on two Ronchi phase gratings in series

Abstract

Shearing interferometers are very popular and have a growing range of applications, especially in the field of optical testing. We describe a new kind of a lateral shearing interferometer. The lateral shear is produced by two Ronchi phase gratings in series. The phase can be shifted by a lateral movement of one grating relative to the other, and the amount of shear can easily be adjusted by variation of the distance of the gratings. The simplicity of the device is an important advantage, especially in the near IR.

Wavefront sensing based on rotated lateral shearing interferometry

“…1 depicts an implementation based on Ronchi gratings where the shear can be varied by changing the distance d between the gratings. Details of the design and properties of a grating-based lateral shearing interferometer with phase stepping are described in [15,3]. The next implementation, (c), is essentially a Mach-Zehnder interferometer.…”

Compact reversal rotationally shearing interferometer

“…7,8 Several new configurations of shearing interferometers have been recently reported for just such applications. [9][10][11] In the shearing interferometric methods the wave front under test is made to interfere with itself, after it has been displaced in some direction and amount. There are four basic types of shearing interferometers: vectorial [12][13][14] , radial, rotational, and reversal.…”

Three-degree-of-freedom displacement measurement using grating-based heterodyne interferometry

“…The orthogonality of the two interferometers is essential to provide precision, otherwise measurement error will be induced by orthogonal alignment of the two interferometers. Schreiber and Schwider [18] developed a GI with two Ronchi gratings that is able to measure 2-DOF displacement. However, the 2-DOF measurement can only be obtained if the optical configuration changes.…”