Quantum Optics with Semiconductors
Thresholdless THz Lasers with Strongly Coupled Cavities.
Negatively Refracting Quantum Metamaterials for Perfect Lensing
Laser imaging for Cancer Diagnosis
Science Communication Activities
I first came to Imperial from Cambridge in 1979 and, apart from spells working in the US (at UC Santa Barbara) and for the BBC, have been here ever since, joining the faculty in 1985. I am Head of the Optoelectronics section. I have experienced all aspects of the academic’s job, from giving large UG lecture courses (and winning awards for them), managing MSc. Programmes and large research collaborations, to the whole spectrum of teaching, examining, recruitment and promotions tasks. Currently I have a live grant portfolio of >£1.5M, mostly from EPSRC and an aggregate total of >£10m.. I have more than 280 publications, and graduated 26 PhD students with a 100% sucess rate. I served as Dean of the Faculty of Natural Sciences from 2009. Nowadays I do a lot of committee work for other HEI’s and on international panels.
My research centres on Quantum Optical Effects in Nanostructures. We are probably best known for making semiconductor nanostructured "artificail atoms" which vanish temporarily when hit with with invisible laser beams (see link above) using a quantum interference effect known as EIT.
However, we have also used our spectroscopt expertise to develop a new mid-IR medical imaging method for detecting cancer. It works by using mid-IR absorption to measure the ratios of chemical in a tissue slice taken from a suspected cancer site. At the moment clinicians diagnose and monitor the disease by subjectively grading these slices visually, after they have been stained with "H+E" vegetable dyes.
Our technique augments this "H+E" protocol, but its a quantitative measure of the chemical changes (specifically the ratio of the concentration of phosphate groups from the DNA to the amount of Amide groups from cell proteins) known to accompany the disease, and we believe this will make it more selective and sensitive a measure than current histopathology. We've made and patented a prototype machine and its currently undergoing clinical trials with IC cancer specialists at Charing Cross Hospital.
And recently we have shown how the resolution of this technique can, by using state-of-the-art tuneable QCL (Quantum Cascade Laser) laser arrays, be improved to the point where we can get information about distributions of chemical components within a single cell.
Also I have just been awarded a grant to study a new form of "Quantum-Ratcher" Solar cell that our theories say should give an ultra-high conversion efficiency. It works by designing in triple set of optical transitions that each absorbs a targeted part of the solar spectrum in a way that significantly exceeds the so-called "Shockley-Quiesser" theoretical efficiency limit for a conventional cell.
Finally, we have pioneered the idea of "Quantum Metamaterials", where we use Quantum theory in semiconductor nanostructures to make a new type of lens that produces images that are much sharper than conventional lenses that are limited by diffraction theory.
I think scienec communication and our reach is very important and I give international public lecture tours, often at Science festivals in India and, of all places, Kazakhstan. I'm often asked the give TV interviews on t behalf of the College, and I officiate at International competitions for youngsters.
My personal interests include my family, The Great Outdoors, catamaran sailing and playing jazz. I have rowed across the channel 3 times, including a 500mile race from London to Paris (which we won!).
et al., 2016, New IR imaging modalities for cancer detection and for intra-cell chemical mapping with a sub-diffraction mid-IR s-SNOM, Faraday Discussions, Vol:187, ISSN:1364-5498, Pages:539-553
et al., 2016, Quantum cascade photon ratchets for intermediate band solar cells, Ieee Journal of Photovoltaics, Vol:6, ISSN:2156-3381, Pages:673-678
et al., 2016, Harnessing a Quantum Design Approach for Making Low-Loss Superlenses, Nano Letters, Vol:16, ISSN:1530-6984, Pages:1609-1613
et al., 2013, Widely tuneable scattering-type scanning near-field optical microscopy using pulsed quantum cascade lasers, Applied Physics Letters, Vol:103, ISSN:0003-6951
et al., 2012, Digistain: a digital staining instrument for histopathology, Optics Express, Vol:20, ISSN:1094-4087, Pages:7290-7299
et al., 2006, Gain without inversion in semiconductor nanostructures, Nature Materials, Vol:5, ISSN:1476-1122, Pages:175-178
et al., 2005, Ac stark splitting and quantum interference with intersubband transitions in quantum wells, Physical Review Letters, Vol:94, ISSN:0031-9007
et al., 2000, Laser-induced quantum coherence in a semiconductor quantum well, Physical Review Letters, Vol:84, ISSN:0031-9007, Pages:1019-1022