Εξειδίκευση τύπου :	Άρθρο σε επιστημονικό περιοδικό
Τίτλος:	Ultrashort pulse induced modification in ULE - from nanograting formation to laser darkening
Δημιουργός/Συγγραφέας:	Richter S. Möncke D. Zimmermann F. [EL] Καμίτσος, Ευστράτιος Ι.[EN] Kamitsos, Efstratios I. Wondraczek L. Tünnermann A. Nolte S.
Εκδότης:	OSA - The Optical Society
Ημερομηνία:	2015
Γλώσσα:	Αγγλικά
ISSN:	2159-3930
DOI:	10.1364/OME.5.001834
Περίληψη:	We report on ultrashort pulse laser induced modifications in ultra-low expansion (ULE) glass. This silicate glass has a significant fraction of TiO2 (7.5 wt%) to ensure a low thermal expansion. Ultrafast laser irradiation generates different kinds of modifications in this glass: so-called nanogratings are formed when low irradiation power is used; while high laser powers result in heat accumulation and induce local melting. In addition, for almost all laser parameters applied, the processed material tends toward darkening. With help of Small Angle X-ray Scattering (SAXS), Focused Ion Beam (FIB) milling and optical retardance measurements we analyzed the structure of laser induced nanopores which are the basic components of nanogratings. Investigation of the mechanisms responsible for laser induced darkening were conducted by multiple techniques such as FIB milling, Electron Spin Resonance (ESR) and Raman spectroscopy.We could identify the formation of hollow cavities filled with molecular oxygen surrounded by a compressed shell of glass which contains trivalent titanium. While light scattering on the cavities causes opacity, the reduction of colorless Ti4+ (d0) to blue Ti3+ (d1) is responsible for the darkening. By combining the inscription of nanogratings with laser induced darkening it is easily possible to locally tune the type of the modification by three independent degrees of freedom (retardance, orientation of optical axis, amount of darkening) rendering ULE an ideal material for future data storage applications.
Τίτλος πηγής δημοσίευσης:	Optical Materials Express
Τόμος/Κεφάλαιο:	5
Τεύχος:	8
Σελίδες:	1834-1850
Θεματική Κατηγορία:	[EL] Φυσική και θεωρητική χημεία[EN] Physical and theoretical chemistry [EL] Φασματοσκοπία[EN] Spectroscopy
Αξιολόγηση από ομότιμους (peer reviewed):	Ναι
Κάτοχος πνευματικών δικαιωμάτων:	© 2015 Optical Society of America.
Όροι και προϋποθέσεις δικαιωμάτων:	All Open Access, Gold
Εμφανίζεται στις συλλογές:	Ινστιτούτο Θεωρητικής και Φυσικής Χημείας (ΙΘΦΧ) - Επιστημονικό έργο