title: Multi-level diffractive optical elements produced by excimer laser ablation of sol-gel.
abstract: Material ablation by excimer laser micromachining is a promising approach for structuring sol-gel materials as we demonstrate in the present study. Using the well-known direct etching technique, the behaviour of different hybrid organic/inorganic self-made sol-gel materials is examined with a KrF* laser. Ablated depths ranging from 0.1 to 1.5 microm are obtained with a few laser pulses at low fluence (< 1 J/cm(2)). The aim is to rapidly transfer surface relief multi-level diffractive patterns in such a substrate, without intermediate steps. The combination with the 3D profilometry technique of coherence probe microscopy permits to analyse the etching process with the aim of producing multi-level Diffractive Optical Elements (DOE). Examples of four-level DOEs with 10 microm square elementary cells are presented, as well as their laser reconstructions in the infrared.
authors.affiliation: Department of Physics and Nanotechnology, Aalborg University, Aalborg Øst, Denmark. estelle.neiss@lsp.u-strasbg.fr
authors.forename: Estelle
authors.initials: E
authors.lastname: Neiss
authors.forename: Manuel
authors.initials: M
authors.lastname: Flury
authors.forename: Loïc
authors.initials: L
authors.lastname: Mager
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Rehspringer
authors.forename: Alain
authors.initials: A
authors.lastname: Fort
authors.forename: Paul
authors.initials: P
authors.lastname: Montgomery
authors.forename: Philippe
authors.initials: P
authors.lastname: Gérard
authors.forename: Joël
authors.initials: J
authors.lastname: Fontaine
authors.forename: Stéphane
authors.initials: S
authors.lastname: Robert
mesh_terms: D004867:Equipment Design / Q000295:instrumentation* / Q000379:methods*; D019544:Equipment Failure Analysis; D005782:Gels / Q000737:chemistry* / Q000528:radiation effects; D007834:Lasers; D012031:Refractometry / Q000295:instrumentation*; D041623:Tomography, Optical Coherence / Q000379:methods*
chemical_list: D005782:Gels