Stafford Withington

University Professor of Analytical Physics

Stafford.Withington@dow.cam.ac.uk

College telephone number

Current research:

My work is concerned with the development of techniques for observing astronomical sources at wavelengths of between 1mm and 100 microns, or equivalently between the radio and far-infrared. This part of the electromagnetic spectrum, sometimes known as the THz region, is rich in information about the formation of stars in our own galaxy, the formation of galaxies in the very early Universe, and the nature of the exotic physical processes that were at work in the Big Bang itself. Recently, we were awarded a £5M grant by the Particle Physics and Astronomy Research Council to develop an instrument that will search for gravity waves in the earliest moments of the Big Bang. We will attempt to find structure in the polarisation state of the Cosmic Microwave Background Radiation that was established when the Universe was only 1x10^-35 sec old. The instrument will be sited on a high plateau in the Atacama Desert in Chile. To construct extremely sensitive instruments for THz frequencies, it is necessary to develop many new kinds of technology. A large grant from the Government allowed us to establish a superconducting detector and microcircuit fabrication laboratory, which will be used for developing the advanced devices needed for our work. This award was enhanced greatly by a major donation of equipment, staff, and intellectual property by Oxford Instruments PLC. In addition to superconducting device physics, it is important to understand precisely how to extract the required astronomical information from the incoming radiation field, and for this reason I work extensively on theoretical classical and quantum THz optics.

Some recent publications:

1. S. Withington, G. Saklatvala, and M.P. Hobson, Partially coherent analysis of imaging and interferometric phased arrays: noise, correlations, and fluctuations, J. Opt. Soc. Am. A 23, to be published (2006).
2. S. Withington, M.P. Hobson, and G. Saklatvala, Quantum-statistical analysis of multimode far-infrared and submillimetre-wave astronomical interferometers, J. Opt. Soc. Am. A 22, 1937-1946 (2005).
3. S. Withington, E.S. Campbell, and M.P. Hobson, A numerical procedure for simulating the behavior of multimode, bolometric, astronomical interferometers, J. Applied Physics, 97, 124909 (2005).
4. S. Withington, Terahertz astronomical telescopes and instrumentation, Phil. Trans. R. Soc. Lond. A 362, 395-402 (2004).
5. S. Withington, M.P. Hobson, and E.S. Campbell, Modal foundations of close-packed optical arrays with particular application to infrared and millimeter-wave astronomical interferometry, J. Applied Physics 96, (2004).
6. S. Withington, M.P. Hobson, and E.S. Campbell, Modal analysis of astronomical bolometric interferometers, J. Opt Soc. Am. A 21, (2004).
7. R.H. Berry, M.P. Hobson, and S. Withington, General approach for representing and propagating partially coherent terahertz fields with application to Gabor basis sets, J. Opt. Soc. Am. A 21, 786-796 (2004).
8. S. Withington, M.P. Hobson, and R.H. Berry, Representing the behaviour of partially coherent optical systems by using overcomplete basis sets, J. Opt. Soc. Am. A 21, 207-217 (2004).
9. S. Withington, P. Kittara, and G. Yassin, Multitone quantum simulations of saturating tunnel junction mixers,J. Applied Physics 93, 9812-9822 (2003)