Flipping the sign of refractive index changes in ultrafast and temporally shaped laser-irradiated borosilicate crown optical glass at high repetition rates
- Laboratoire Hubert Curien, UMR 5516 CNRS, Universite Jean Monnet, 42000 Saint Etienne (France)
- Institute of Thermophysics SB RAS, 630090 Novosibirsk (Russian Federation)
- Design and Technology Branch of Lavrentyev Institute of Hydrodynamics SB RAS, 630090 Novosibirsk (Russian Federation)
- Max-Born-Institut fuer Nichtlineare Optik und Kurzzeitspektroskopie, 12489 Berlin (Germany)
Ultrafast subpicosecond laser exposure usually induces negative refractive index changes in optical glasses with strong thermal expansion such as borosilicate BK7 due to volume expansion and mechanical rarefaction. We show that temporally shaped laser excitation on picosecond scales and at high repetition rates can invert the regular material response resulting in a significant refractive index increase. Simulations of pulse propagation and evolution of heat and strain waves in BK7 glass exposed to different pulse durations were performed to understand mechanisms of refractive index increase. Narrow spatial distribution of energy for optimized picosecond pulses determines shock-induced plastic deformations accompanied by partial healing of the lateral strain due to preferential heat flow. The matter momentum relaxation produces directional on-axis material compaction.
- OSTI ID:
- 21143106
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 77, Issue 10; Other Information: DOI: 10.1103/PhysRevB.77.104205; (c) 2008 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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