Terahertz Spectroscopy Meeting

RSC East Anglia Region and RSC Molecular Spectroscopy Group joint meeting on:

Terahertz spectroscopy - state of the art and future perspectives

The RSC EAR and RSC MSG held a joint meeting on THz spectroscopy on 28 October 2009 at Gonville & Caius College, Cambridge University. The meeting was hosted and the programme put together by Dr. Axel Zeitler (University of Cambridge).

The meeting brought together the leading UK researchers in the THz spectroscopy community to give an introduction into the technology, its applications, the interpretation of the experimental data and an outlook into the future of this important new field of spectroscopy.

The meeting attracted 38 delegates, which included 8 speakers; a large proportion of the delegates were students. The meeting was considered both a technical and networking success; it brought together current practitioners in the technique from a diverse range of application areas. Post-meeting feedback was very positive, and with this in mind, consideration is being given by the community to repeat such a meeting next year and thus build up a communication platform for this rapidly evolving field of spectroscopy.

A brief for THz spectroscopy is given below, followed by the speaker programme for this meeting.

THz spectroscopy: Terahertz spectroscopy is an exciting field of vibrational spectroscopy that has an excellent potential for the physico-chemical characterisation of materials but it is, as yet, largely under-explored. Recent developments in semiconductor physics have made it possible to provide light at terahertz frequencies (a frequency of 1 THz equals a wavelength of 0.3 mm or a wavenumber of 33 cm‑1) in a relatively simple way. Light located in this range of the electromagnetic spectrum was very difficult to generate previously. It has unique properties in that it easily penetrates through a number of materials, such as polymers, which are opaque at visible frequencies. As well as being a non-destructive probe of materials, terahertz radiation has the important property that it interacts with vibrational modes that extend across large domains of a crystal lattice. This makes terahertz spectroscopy unique: even though it is possible to excite molecules using a variety of energies it is only through the careful selection of the low energy in the terahertz range that it is possible to selectively excite crystal lattice vibrations and study in a unique way the presence and nature of interactions between molecules. The broad range of applications for terahertz spectroscopy is rounded off by its ability to study hydrogen boding interactions in liquids – and hence opening a whole field of applications in the life sciences – while in gases rotational transitions can be investigated in detail.Technical talks:

1. Introduction to terahertz spectroscopy

Axel Zeitler (Department of Chemical Engineering, University of Cambridge)

2. Understanding the vibrational modes at terahertz frequencies

Graeme Day (Department of Chemistry, University of Cambridge)

3. Terahertz spectroscopic imaging

Yaochun Shen (Department of Electrical Engineering, University of Liverpool)

4. Recent developments in terahertz spectroscopy instrumentation

Philip Taday (TeraView Ltd., Cambridge)

5. THz spectroscopy with neutrons

Stewart Parker (Rutherford Appleton Laboratory, Didcot)

6. Terahertz spectroscopy in the life sciences

Martyn Chamberlain (Department of Physics, University of Durham)

7. Materials characterisation using terahertz spectroscopy

Edward Parrott (Department of Chemical Engineering, University of Cambridge)

8. Polarisation sensitive and pump probe terahertz spectroscopy

Michael Johnston (Clarendon Laboratory, University of Oxford)

9. Terahertz spectroscopy of combustion processes

Mark Stringer (School of Electronic and Electrical Engineering, University of Leeds)

10. Applications of terahertz spectroscopy in the pharmaceutical industry

Axel Zeitler (Department of Chemical Engineering, University of Cambridge)

John Chalmers, RSC MSG Chair, and Axel Zeitler. November 2009