Institution: | (1) Femtosecond Optics Group, Department of Physics, Imperial College of Science and Technology, Prince Consort Road, London SW7 2BZ, UK (Fax: +44-171/594-7782), UK;(2) Philips Optoelectronics Centre, Prof. Holstlaan 4, 5656 AA Eindhoven, The Netherlands, NL |