Two different optical techniques for surface tracking and linewidth measurement are evaluated. First, an evaluation is made of the performance of a double-focus polarization microscope, based on results from a computer model and from experimental measurements. The assessment shows that a phase curvature effect makes the operation of this configuration impractical as a surface tracking device and linewidth measurement system. An alternative arrangement of using a double aperture is evaluated. The phase curvature effect is reduced in this type of microscope. A practical optical arrangement to implement a double-aperture microscope is given.
© 2000 Optical Society of America
Original Manuscript: August 25, 1999
Revised Manuscript: February 10, 2000
Published: May 1, 2000
Sarah A. Barman, John G. Walker, John W. Nunn, Nicholas P. Turner, and Michael J. Downs, "Phase effects in double-focus and double-aperture interference microscopy," Appl. Opt. 39, 2159-2166 (2000)