Mark Frogley
Infrared Microspectroscopy

Mark Frogley is the Beamline Scientist on the Infrared Beamline, B22. He joined Diamond from the physics department of Imperial College London. His recent research is in quantum and non-linear optics in semiconductor nanostructures and devices, and he is interested in the development of novel spectroscopic instrumentation and techniques.

Email: Mark Frogley
Tel: +44 (0) 1235 778721
Beamline B22: Infrared Microspectroscopy

Key Research Areas

Semiconductor physics, nonlinear and quantum optics, electronic and vibrational spectroscopy, nonlinear elasticity, Raman spectroscopy, nanotechnology.

Current Research Interests

Quantum optics in semiconductors
Semiconductors can be engineered on the scale of an atomic bond to behave like artificial atoms, with sharp spectral lines. Like real atoms, when subjected to intense light of specific wavelengths, the electronic states become "dressed" and the optical properties are radically different to the natural state. I am interested in controlling these dressed states to make novel optoelectronic devices. Working with Chris Phillips of Imperial College London I demonstrated dressing of states in quantum wells, and by making the states interfere, induced optical gain in the medium but without population inversion – a condition which until now has limited the performance of all solid state laser devices.

Because driving these artificial atoms with intense light controls their quantum state, this technique might be used to process quantum information (QI) for secure communication and powerful computation. I am currently investigating the concept in quantum wells and lower dimensional nanostructures. Colloidal nanoparticles, for example, could be made into macroscopic composite materials for quantum control of photonic QI, or patterned into arrays where individual particles (instead of photons) act as single quantum bits. I am developing a time-resolved pump-probe spectroscopy instrument to investigate the electron dynamics of these systems, exploiting pulsed (~10ps) synchrotron radiation to probe the visible to far-infrared transitions.

Nanoparticle composites and interfaces
Nanoparticles and their composites have outstanding electronic and mechanical properties, and devices have been demonstrated for visual displays and artificial muscles, nanowires and ultra-strong materials. A critical factor is the interface between the nanoparticle and its environment, and I am interested in characterising that interface using vibrational spectroscopy. As well as system composition, the IR spectrum can reveal the conformation or strain state, for example the local strain transfer between the host matrix and filler in composites. I am planning a near-field capability for the IR beamline at Diamond which will enable detailed chemical-imaging of nanoparticles and the nanoparticle/matrix interface and am interested in applying these techniques to problems such as cell adhesion in the life sciences.

Selected Publications

1. "Gain without inversion in semiconductor nanostructures", Frogley, M.D., Dynes, J.F., Beck, M., Faist, J. and Phillips, C.C.  NATURE MATERIALS 5 175 (2006)
2. "All-optical switching in quantum cascade lasers", Zervos, C., Frogley, M. D., Phillips, C. C., Kundys, D. O., Wilson, L. R., Hopkinson, M. and Skolnick, M. S.  APPLIED PHYSICS LETTERS 90 053505 (2007)
3. "AC Stark splitting and quantum interference with intersubband transitions in quantum wells", Dynes, J.F., Frogley, M.D., Beck, M., Faist, J. and Phillips, C.C.  PHYSICAL REVIEW LETTERS 94 157403 (2005)
4. "Coherent near-infrared wavelength conversion in semiconductor quantum cascade lasers", Zervos, C., Frogley, M. D., Phillips, C. C., Kundys, D. O., Wilson, L. R., Cockburn, J.W., Hopkinson, M. and Skolnick, M. S.  APPLIED PHYSICS LETTERS 89 183507 (2006)
5. "Carbon nanotubes: From molecular to macroscopic sensors", Wood, J.R., Zhao, Q., Frogley, M.D., Meurs, E.R., Prins, A.D., Peijs, T., Dunstan, D.J. and Wagner, H.D.  PHYSICAL REVIEW B 62 7571 (2000)