Dear Mems collegues: Does anybody know where can I buy SiO2 substrate, polished double side with optical quality of flatness ? Also, BK7 is ok. Thanks in advance. Sincerely, Christophe Gorecki ******************************************************************* Dr. Christophe Gorecki, Senior Researcher Laboratoire d'Optique P.M. Duffieux, Université de Franche-Comté 16 Rte de Gray, 25030 Besançon Cedex, France Tel: +33-3-81666607, fax: 33-3-816666423 e-mails: christophe.gorecki@univ-fcomte.fr / christophe.gorecki@wanadoo.fr