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Applied Optics

Applied Optics

APPLICATIONS-CENTERED RESEARCH IN OPTICS

  • Vol. 31, Iss. 31 — Nov. 1, 1992
  • pp: 6772–6782

Interferometric scanning optical microscope for surface characterization

M. Jeff Offside and Michael G. Somekh  »View Author Affiliations


Applied Optics, Vol. 31, Issue 31, pp. 6772-6782 (1992)
http://dx.doi.org/10.1364/AO.31.006772


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Abstract

A phase-sensitive scanning optical microscope is described that can measure surface height changes down to 0.1 nm. This is achieved by using two heterodyne Michelson interferometers in parallel. One interferometer probes the sample with a tightly focused beam, and the second has a collimated beam that illuminates a large area of the surface, providing a large area on sample reference. This is facilitated by using a specially constructed objective lens that permits the relative areas illuminated by the two probe beams to be varied both arbitrarily and independently, thus ensuring an accurate absolute phase measurement. We subtracted the phase outputs from each interferometer to provide the sample phase information, canceling the phase noise resulting from microphonics in the process. Results from a prototype version of the microscope are presented that demonstrate the advantages of the system over existing techniques.

© 1992 Optical Society of America

History
Original Manuscript: December 18, 1991
Published: November 1, 1992

Citation
M. Jeff Offside and Michael G. Somekh, "Interferometric scanning optical microscope for surface characterization," Appl. Opt. 31, 6772-6782 (1992)
http://www.opticsinfobase.org/ao/abstract.cfm?URI=ao-31-31-6772


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References

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  21. In practice this is an approximation caused by the effects of shadowing. However, the application of our instrument is primarily for the examination of objects with nanometer-scale topography for which the pure phase object representation is valid.
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