title: Structural characterization of femtosecond laser modified regions inside sapphire.
abstract: We report on structural characterization of sapphire photomodified by voids of sub-wavelength diameter surrounded by amorphised regions formed after exposure by tightly-focused femtosecond laser pulses of 800 nm wavelength and 150 fs duration at the single and double-pulse irradiation inside crystalline sapphire. Regrowth of a crystalline phase near the edge between the amorphous and crystalline phases was observed by transmission electron microscopy (TEM) in the case of double-pulse-irradiated locations. Regions patterned by single-pulse-induced voids inside sapphire were characterized by synchrotron X-ray diffraction (XRD) technique. The XRD patterns indicate presence of an expanded phase of the host crystal. The origin of structural changes observed in TEM and XRD is discussed and is consistent with fast thermal quenching.
authors.affiliation: Centre for Micro-Photonics, Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Hawthorn, Vic 3122, Australia.
authors.forename: Saulius
authors.initials: S
authors.lastname: Juodkazis
authors.forename: Shinji
authors.initials: S
authors.lastname: Kohara
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Ohishi
authors.forename: Norihisa
authors.initials: N
authors.lastname: Hirao
authors.forename: Arturas
authors.initials: A
authors.lastname: Vailionis
authors.forename: Vygantas
authors.initials: V
authors.lastname: Mizeikis
authors.forename: Akira
authors.initials: A
authors.lastname: Saito
authors.forename: Andrei
authors.initials: A
authors.lastname: Rode
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry* / Q000528:radiation effects*; D007834:Lasers; D008422:Materials Testing; D049329:Nanostructures / Q000737:chemistry / Q000528:radiation effects* / Q000648:ultrastructure*; D010316:Particle Size; D011829:Radiation Dosage; D013499:Surface Properties / Q000528:radiation effects
chemical_list: D000537:Aluminum Oxide