[1] Fraunhofer Ctr Appl Photon, Technol & Innovat Ctr, 99 George St, Glasgow G1 1RD, Lanark, Scotland
[2] Heriot Watt Univ, Inst Photon & Quantum Sci, David Brewster Bldg, Edinburgh EH14 4AS, Midlothian, Scotland
[3] Tech Univ Denmark, Dept Photon Engn, DTU Foton, DK-2800 Lyngby, Denmark