Optical thickness measurement with multi-wavelength THz interferometry

T. D. Nguyen, Jesus Daniel Valera Robles, A. J. Moore

Research output: Contribution to journalArticle

10 Citations (Scopus)
235 Downloads (Pure)

Abstract

We report unambiguous thickness measurement with an all-optical THz source. The optical thickness variation of a test target was measured in a Mach-Zehnder interferometer to approximately 0.5% of the illumination wavelength using an optical parametric THz laser. The frequency of the laser was continuously tuneable, enabling a synthetic wavelength to be produced by sequential illumination at discrete frequencies, thus extending the unambiguous measurement range to half the synthetic wavelength. The all-optical source provides some advantages with respect to opto-electronic and electronic sources, particularly measurement speed and resolution.

Original languageEnglish
Pages (from-to)19-22
Number of pages4
JournalOptics and Lasers in Engineering
Volume61
Early online date16 May 2014
DOIs
Publication statusPublished - Oct 2014

Keywords

  • Interferometry
  • Metrology
  • Phase-step
  • Synthetic wavelength
  • THz

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering
  • Atomic and Molecular Physics, and Optics
  • Mechanical Engineering

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