Abstract

I propose a symmetric geometry for grazing-incidence interferometry of flat surfaces using diffraction gratings for beam splitting and recombination. The geometry employs a reference mirror to correct for relative inversion of the measurement and reference wave fronts. Preliminary testing with a 4-µm equivalent-wavelength system shows a 3σ repeatability of 20 nm for both smooth and rough surfaces, including a variety of precision-engineered metal, ceramic, and glass objects. The system has a comfortable working distance and large field of view, suitable for production testing.

© 2000 Optical Society of America

Sharp and rectified imaging of plane test objects in diffractive grazing incidence interferometers

J. Schwider
Appl. Opt. 53(5) 988-1000 (2014)

Compensation for anamorphotic distortion in grazing-incidence interferometry testing planar specimens

Jessica Schneider, Klaus Mantel, Roland Schreiner, Norbert Lindlein, and Johannes Schwider
Appl. Opt. 42(22) 4480-4487 (2003)

The Diffraction Grating at Grazing Incidence

Luis W. Alvarez
J. Opt. Soc. Am. 26(9) 343-346 (1936)

Testing of rod objects by grazing-incidence interferometry: experiment

Sven Brinkmann, Thomas Dresel, Roland Schreiner, and Johannes Schwider
Appl. Opt. 38(1) 121-125 (1999)

Interferometric grazing incidence test of rough steep convex spherical and aspherical surfaces: first simulations and experimental proof of principle

S. Rothau, N. Lindlein, and J. Schwider
Appl. Opt. 58(33) 9082-9088 (2019)