[1] STN SPERIMENTALE VETRO,I-30141 MURANO,ITALY
[2] UNIV PADUA,DIPARTIMENTO FIS,INFM,I-35131 PADUA,ITALY
[3] ENEA CASACCIA,IN,FIS,DIAF,I-00060 ROME,ITALY
[4] CTR ETUD SACLAY,LAB LEON BRILLOUIN,F-91191 GIF SUR YVETTE,FRANCE
[5] ENEA CASACCIA,THIN FILM OPT LAB,I-00060 ROME,ITALY
[6] UNIV PADUA,DIPARTIMENTO INGN MECCAN,INFM,I-35141 PADUA,ITALY