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Enhanced formation of nanogratings inside fused silica due to the generation of self-trapped excitons induced by femtosecond laser pulses

 
: Richter, Sören; Jia, Fei; Heinrich, Matthias; Döring, Sven; Nolte, Stefan; Tünnermann, Andreas

:

Heisterkamp, Alexander (Ed.) ; Society of Photo-Optical Instrumentation Engineers -SPIE-, Bellingham/Wash.:
Frontiers in Ultrafast Optics: Biomedical, Scientific, and Industrial Applications XII : 21 - 26 January 2012, Moscone Center, San Francisco, California United States
Bellingham, WA: SPIE, 2012 (Proceedings of SPIE 8247)
ISBN: 978-0-8194-8890-9
Paper 82470N
Conference "Frontiers in Ultrafast Optics - Biomedical, Scientific, and Industrial Applications" <12, 2012, San Francisco/Calif.>
English
Conference Paper
Fraunhofer IOF ()
nanograting; femtosecond laser materials processing; self trapped excitions; defect; fused silica

Abstract
To gain insight into the processes mediating the cumulative action of subsequent laser pulses which gives rise to the formation of nanogratings, we performed double pulse experiments with femtosecond laser pulses with a delay time ranging from 0.5 ps to 1 ns. We determined the polarisation contrast intensity of the inscribed lines as a measure for the birefringent strength of the nanogratings. Our experiments show an enhanced nanograting formation for pulse separations below 500 ps. We attribute this to the presence of self trapped excitons serving as transient material memory enhancing the impact of the second pulse. In contrast, nanograting formation at pulse separation times up to several seconds is being mediated by dangling bond type defects as evidenced by spectrally resolved absorption measurements.

: http://publica.fraunhofer.de/documents/N-194598.html