Mark Frogley

Solid state physics Non-linear optics Nanotechnology Optical spectroscopy Vibrational spectroscopy.

In collaboration with Prof. Chris Phillips of Imperial College London, we develop novel materials and devices based on infrared intersubband transitions (ISBTs) in semiconductor nanostructures. The energies and couplings between these electronic states can be designed for novel optoelectronic devices such as lasers and solar cells. These crystalline metamaterials can even behave as "artificial atoms" where the quantum coherence of states leads to exotic behaviours such as quantum interference and optical gain without population inversion. Such coherent control promises a new generation of devices e.g. for processing secure quantum information.

At Diamond, we are investigating ISBT "quantum cascade" devices which are being developed as next generation IR light sources but also exhibit quantum coherent behaviour due to strong light-matter coupling in the laser cavity. The high brightness synchrotron IR beam allows us to understand the electron dynamics in the microscopic sized devices, during operation, using time resolved infrared microspectroscopy. We are also developing patented "quantum ratchet" solar cells which use large numbers of quantum wells with different energy states to harvest a wider spectral range of sunlight than normally possible. The high brightness and ultrabroadband IR beam allows us to understand and develop the devices under illumination conditions similar to maximally concentrated solar radiation. The pulsed nature of the IR beam provides information on the electron dynamics.

With Dr. Asa Barber at Queen Mary University of London, we developed a nanoscale mechanical testing system with in-situ infrared microspectroscopy, to follow molecular deformations of natural and synthetic micro/nanofibres and samples cut from microstructured materials. We can determine the instrinsic behaviours of different phases and the interface properties: local molecular behaviour can be correlated with the local stress/strain state. We applied this technique to electrospun polymer fibres and graphene oxide papers (collaboration with and Dr. Luqi Liu at the National Center for Nanoscience and Nanotechbology, Beijing) and are investigating the origins of high strength in biomaterials.

• With Prof. Chris Phillips, Imperial College London. We are developing quantum metamaterials from semiconductor nanostrucutres. I lead experiments to characterise the infrared electronic transitions in the materials and operational optoelectronic devices using time-resolved synchrotron infrared microspectroscopy.

• With Dr. Asa Barber, Reader at Queen Mary University of London and Dr. Luqi Liu, Associate Professor at the National Centre for Nanoscience and Technology, Beijing. We study the origins of high mechanical performance in biomaterials, and develop synthetic novel nano/microstructured materials. I lead infrared microspectroscopy experiments in-situ during nanomechanical tests to quantify molecular level structure and deformation and relate this to local mechanical properties. 

• "Amine-terminated nanoparticle films: pattern deposition by a simple nanostencilling technique and stability studies under x-ray irradiation" Coxon, P.R., Ashby ,S., Ahire, J., Frogley, M.D., and Chao, Y., PHYICAL CHEMISTRY CHEMICAL PHYSICS In Press (2014)
   
• "Deformation and failure mechanisms in graphene oxide paper using in situ nanomechanical tensile testing", Wang, C., Frogley, M.D., Cinque, G., Liu, L-Q. and Barber, A.H. CARBON 63 471 (2013)
   
• "Monitoring the activation of copper-containing zeotype catalysts prepared by direct synthesis using in situ synchrotron infrared microcrystal spectroscopy and complementary techniques", Eschenroeder, E.C.V., Turrina, A., Picone, A.L., Cinque, G., Frogley, M.D., Cox, P.A., Howe, R.F. and Wright, P.A. CHEMISTRY OF MATERIALS In Press and available online (2013)
   
• "The effect of optical substrates on micro-FTIR analysis of single mammalian cells", Wehbe, K., Filik, J., Frogley, M.D. and Cinque, G., ANALYTICAL AND BIOANALYTICAL CHEMISTRY 405 1311 (2013)
   
• "Electric field standing wave artefacts in FTIR micro-spectroscopy of biological materials", Filik, J., Frogley, M.D., Pijanka, J.K., Wehbe, K. and Cinque, G., ANALYST 137 853 (2012)
   
• "Isolating stem cells in the inter-follicular epidermis employing synchrotron radiation-based Fourier-transform infrared microspectroscopy and focal plane array imaging", Patel, I.I., Harrison, W.J., Kerns, J.G., Filik, J., Wehbe, K., Carmichael, P.L., Scott, A.D., Philpott, M.P., Frogley, M.D., Cinque, G. and Martin F.L., ANALYTICAL AND BIOANALYTICAL CHEMISTRY 404 1745 (2012)
   
• "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) "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)

As senior beamline scientist, my key role is in the support of user experiments including tailored optical setups for unusual experiments, developing sample enviroments for a wide range of applications, and data analysis. I assist in design and development of the infrared beamline and endstations. As well as my own scientific research, I conduct in house research as part of the beamline team, which is currently focussed on super-resolution infrared imaging.