[1] Fdn Res & Technol Hellas, Inst Elect Struct & Laser, Iraklion 71110, Crete, Greece
[2] Univ Crete, Dept Phys, Iraklion 70013, Greece
[3] Bundesanstalt Mat Forsch & Prufung BAM, D-12205 Berlin, Germany
[4] Johannes Kepler Univ Linz, Inst Appl Phys, A-4040 Linz, Austria
[5] CSIC, Laser Proc Grp, Inst Opt IO, Madrid 28006, Spain
[6] Univ Crete, Dept Mat Sci & Technol, Iraklion 70013, Greece
[7] Rhein Westfal TH Aachen, Inst Zool, D-52074 Aachen, Germany
[8] Johannes Kepler Univ Linz, Inst Biomed Mechatron, A-4040 Linz, Austria