Laser Spectroscopy

Electronic transitions in solids are inhomogeneously broadened through the variation of local fields: each optical centre has a different local environment, even in well defined single crystals, due to imperfections and isotope distributions. The energy of an electronic transition depends on the local field, and thus varies over a range reflecting its distribution. Typical inhomogeneous widths of excitations in crystals are of the order of magnitude of 30 GHz (=1 cm^-1 ) respectively, whereas the homogeneous width can approach the limit imposed by the excited state lifetime and be as narrow as 100 Hz (=3 10 ^-9cm^-1 ) at liquid helium temperatures.

Laser based techniques such as spectral hole-burning, fluorescence line narrowing and coherent transient spectroscopy, can overcome the inhomogeneous broadening and extremely narrow features can be measured. The main goal of the Laser Spectroscopy research group is to apply laser based techniques to chemically interesting system, including X-ray storage phosphors, nanoparticles and transition metal ions at extreme dilutions. Besides of delivering valuable results for a better understanding of electronic structure in the solid state, the prevailing driving force behind these spectroscopic studies are the potential applications in data storage and signal processing. Although conventional semiconductor based electronics and magnetic storage are the dominating technologies today, the ever increasing demands for high capacity, high speed storage and processing warrants investigations into optical computing and optical data storage. We are convinced that conventional technologies will be superseded by all-optical technology over the next decades.

Academic Staff:

Assoc. Prof. Hans Riesen (Group Leader) (h.riesen@adfa.edu.au) Dr phil.-nat., lic. phil.-nat. (University of Berne, Switzerland)

Visiting Fellow:

Brendan Hayward

Research Assistants:

Elizabeth Campbell (Part time)
Tracy Massil

Current Honours Student:

Thomas Monks-Corrigan – Research Topic – Spectral hole-burning studies of Manganese(IV) in crystals and nanoparticles, 2007-2008.

Recent Honours Student:

Jarred Croft – Research Topic - High resolution laser spectroscopic techniques in Chromium (III) coordination compounds, 2006.

Research Collaborators:

Emeritus Prof. S. Campbell (PEMS, UNSW@ADFA)
Prof. D. Gamelin (Department of Chemistry, University of Washington, Seattle, USA )
Prof. J. M. Harrowfield (University of Strasbourg, France )
Prof. A. Hauser (University of Geneva, Switzerland )
Emeritus Prof. W. G. Jackson (PEMS, UNSW@ADFA)
Prof. E. Krausz (The Australian National University, Canberra)
Prof. N. B. Manson (The Australian National University, Canberra)
Prof. M. Mizuno (Kanazawa University, Japan
Prof. A. D. Rae (Research School of Chemistry, The Australian National University)
Assoc. Prof. M. Riley (University of Queensland, Brisbane)
Assoc. Prof. M. Stevens-Kalceff (School of Physics, UNSW, Sydney)
Dr A. Szabo (National Research Council of Canada - originator of modern laser spectroscopy of the solid state including FLN and hole-burning spectroscopy)

Members of the Laser Spectroscopy Research Group in February 2008.
From L to R: E. Campbell, T. Massil, Assoc. Prof. H. Riesen, T. Monks-Corrigan.
[Photo Credit: K. Badek]