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Nanaosecond and femtosecond laser ablation of TeO2 crystals: surface characterization and plasma analysis

  • Near-IR femtosecond (fs) (pulse duration = 150 fs, wavelength = 775 nm, repetition rate 1 kHz) and VUV nanosecond (ns) (pulse duration = 20 ns, wavelength = 157 nm, repetition rate 1 to 5 Hz) laser pulse ablation of single-crystalline TeO2 (c-TeO2 ) surfaces was performed in air using the direct focusing technique. A multi-method characterization using optical microscopy, atomic force microscopy and scanning electron microscopy revealed the surface morphology of the ablated craters. This allowed us at each irradiation site to characterize precisely the lateral and vertical dimensions of the laser-ablated craters for different laser pulse energies and number of laser pulses per spot. Based on the obtained information, we quantitatively determined the ablation threshold fluence for the fs laser irradiation when different pulse numbers were applied to the same spot using two independent extrapolation techniques. We found that in the case of NIR fs laser pulse irradiation, theNear-IR femtosecond (fs) (pulse duration = 150 fs, wavelength = 775 nm, repetition rate 1 kHz) and VUV nanosecond (ns) (pulse duration = 20 ns, wavelength = 157 nm, repetition rate 1 to 5 Hz) laser pulse ablation of single-crystalline TeO2 (c-TeO2 ) surfaces was performed in air using the direct focusing technique. A multi-method characterization using optical microscopy, atomic force microscopy and scanning electron microscopy revealed the surface morphology of the ablated craters. This allowed us at each irradiation site to characterize precisely the lateral and vertical dimensions of the laser-ablated craters for different laser pulse energies and number of laser pulses per spot. Based on the obtained information, we quantitatively determined the ablation threshold fluence for the fs laser irradiation when different pulse numbers were applied to the same spot using two independent extrapolation techniques. We found that in the case of NIR fs laser pulse irradiation, the ablation threshold significantly depends on the number of laser pulses applied to the same spot indicating that incubation effects play an important role in this material. In the case of VUV ns laser pulses, the ablation rate is significantly higher due to the high photon energy and the predominantly linear absorption in the material. These results are discussed on the basis of recent models of the interaction of laser pulses with dielectrics. In the second part of this chapter, we use time- of-flight mass spectrometry (TOFMS) to analyze the elemental composition of the ablation products generated upon laser irradiation of c-TeO2 with single fs- (pulse duration ~200 fs, wavelength 398 nm) and ns-pulses (pulse duration 4 ns, wavelength 355 nm). Due to the three order of magnitude different peak intensities of the ns- and fs laser pulses, significant differences were observed regarding the laser-induced species in the plasma plume. Positive singly, doubly and triply charged Te ions (Te+, Te2+, Te3+) in the form of many different isotopes were observed in case of both irradiations. In the case of the ns-laser ablation, the TeO+ formation was negligible compared to the fs case and there was no Te trimer (Te3+) formation observed. It was found that the amplitude of Te ion signals strongly depends on the applied laser pulse energy. Singly charged oxygen ions (O+) are always present as a byproduct in both kinds of laser ablation.zeige mehrzeige weniger

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Metadaten
Autoren/innen:S. Beke, K. Sugioka, K. Midorikawa, Jörn Bonse
Persönliche Herausgeber/innen:E.J. Hemsworth
Dokumenttyp:Buchkapitel
Veröffentlichungsform:Verlagsliteratur
Sprache:Englisch
Titel des übergeordneten Werkes (Englisch):Laser-induced plasmas: theory and applications
Jahr der Erstveröffentlichung:2011
Verlag:Nova Science Publishers, Inc.
Ausgabe/Heft:Chapter 4
Erste Seite:77
Letzte Seite:96
Freie Schlagwörter:Atomic force microscopy; Femtosecond laser ablation; Incubation; Isotopes; Multiphoton absorption; Optical properties; Scanning electron microscopy; Tellurium dioxide crystals; Time-of-flight mass spectroscopy; VUV nanosecond laser ablation
ISBN:978-1-61324-851-5
Bemerkung:
Serientitel: Physics Research and Technology – Series title: Physics Research and Technology
Verfügbarkeit des Volltexts:Papiergebundenes Belegexemplar in der Bibliothek der BAM vorhanden ("Hard-copy Access")
Bibliotheksstandort:Sonderstandort: Publica-Schrank
Datum der Freischaltung:19.02.2016
Referierte Publikation:Nein