Interferometric scanning optical microscope for surface characterization

M. Jeff Offside, Michael Geoffrey Somekh

Research output: Journal article publicationJournal articleAcademic researchpeer-review

8 Citations (Scopus)

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.
Original languageEnglish
Pages (from-to)6772-6782
Number of pages11
JournalApplied Optics
Volume31
Issue number31
DOIs
Publication statusPublished - 1 Jan 1992
Externally publishedYes

Keywords

  • Absolute phase
  • Heterodyne
  • Interferometer
  • Scanning optical microscope

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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