Author Affiliations

D. G. Luke,^†,* R. McBride,^† R Lloyd,^‡ J. G. Burnett,^§ A. H. Greenaway,^§ and J. D. C. Jones^†

^†Department of Physics, Heriot-Watt University, Riccarton, Edinburgh, EH14 4AS, UK

^‡DRA Materials and Structures Department, Farnborough, Hants, GU14 6TD, UK

^§DRA Electronics Division, St. Andrews Road, Great Malvern, Worcs, WR14 3PS, UK

^*Corresponding author: luke@phy.hw.ac.uk