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Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 17, Iss. 23 — Nov. 9, 2009
  • pp: 20631–20641

Dual-frequency imaging using an electrically tunable terahertz quantum cascade laser

Paul Dean, Nor Kamila Saat, Suraj P. Khanna, Mohammed Salih, Andrew Burnett, John Cunningham, Edmund H. Linfield, and A. Giles Davies  »View Author Affiliations

Optics Express, Vol. 17, Issue 23, pp. 20631-20641 (2009)

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We report dual-frequency transmission imaging of polycrystalline materials using an electrically tunable terahertz (THz) frequency quantum cascade laser (QCL). Using our system we are able to obtain images at both 3.05 THz and 3.24 THz in a single two-dimensional scan of a sample. By taking the difference of the natural logarithms of the transmission coefficients obtained at each frequency, the difference-attenuation coefficient is determined, and evaluated for samples of lactose monohydrate, glucose monohydrate, sucrose, and the high explosive PETN. We also demonstrate difference-intensity imaging at these frequencies by combining amplitude modulation of the QCL bias with lock-in detection. Owing to the specific molecular absorption spectra of these materials in the THz frequency range, the samples can be distinguished using our technique.

© 2009 OSA

OCIS Codes
(140.5965) Lasers and laser optics : Semiconductor lasers, quantum cascade
(110.6795) Imaging systems : Terahertz imaging

ToC Category:
Imaging Systems

Original Manuscript: August 27, 2009
Revised Manuscript: October 16, 2009
Manuscript Accepted: October 20, 2009
Published: October 26, 2009

Paul Dean, Nor Kamila Saat, Suraj P. Khanna, Mohammed Salih, Andrew Burnett, John Cunningham, Edmund H. Linfield, and A. Giles Davies, "Dual-frequency imaging using an electrically tunable terahertz quantum cascade laser," Opt. Express 17, 20631-20641 (2009)

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