OSA's Digital Library

Applied Spectroscopy

Applied Spectroscopy


  • Vol. 62, Iss. 3 — Mar. 1, 2008
  • pp: 319–326

Narrow-Line Waveguide Terahertz Time-Domain Spectroscopy of Aspirin and Aspirin Precursors

N. Laman, S. Sree Harsha, and D. Grischkowsky

Applied Spectroscopy, Vol. 62, Issue 3, pp. 319-326 (2008)

View Full Text Article

Acrobat PDF (937 KB)

Browse Journals / Lookup Meetings

Browse by Journal and Year


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

  • Export Citation/Save Click for help


Low frequency vibrational modes of pharmaceutical molecules are dependent on the molecule as a whole and can be used for identification purposes. However, conventional Fourier transform far-infrared spectroscopy (FT-IR) and terahertz time-domain spectroscopy (THz-TDS) often result in broad, overlapping features that are difficult to distinguish. The technique of waveguide THz-TDS has been recently developed, resulting in sharper spectral features. Waveguide THz-TDS consists of forming an ordered polycrystalline film on a metal plate and incorporating that plate in a parallel-plate waveguide, where the film is probed by THz radiation. The planar order of the film on the metal surface strongly reduces the inhomogeneous broadening, while cooling the waveguide to 77 K reduces the homogeneous broadening. This combination results in sharper absorption lines associated with the vibrational modes of the molecule. Here, this technique has been demonstrated with aspirin and its precursors, benzoic acid and salicylic acid, as well as the salicylic acid isomers 3- and 4-hydroxybenzoic acid. Linewidths as narrow as 20 GHz have been observed, rivaling single crystal measurements.

Virtual Issues
Vol. 3, Iss. 4 Virtual Journal for Biomedical Optics

N. Laman, S. Sree Harsha, and D. Grischkowsky, "Narrow-Line Waveguide Terahertz Time-Domain Spectroscopy of Aspirin and Aspirin Precursors," Appl. Spectrosc. 62, 319-326 (2008)

Sort:  Journal  |  Reset


References are not available for this paper.

Cited By

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.

« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited