2008 Conference on Lasers and Electro-Optics and 2008 Conference on Quantum Electronics and Laser Science, 2008
Time-resolved study of the dielectric function of femtosecond laser excited bismuth demonstrates ... more Time-resolved study of the dielectric function of femtosecond laser excited bismuth demonstrates that excitation of coherent phonons leads to a solid-plasma phase transition, and into a quasi-stable excited state lasting up to 4 ns.
ABSTRACT We present time-resolved dual-angle single-wavelength pump-probe study of the reflectivi... more ABSTRACT We present time-resolved dual-angle single-wavelength pump-probe study of the reflectivity of femtosecond laser excited bismuth crystal. The recovered real and imaginary parts of the dielectric function show complex a transition to a new quasi-stable excited state at about 20 ps. This state lasts for about 4 ns after the excitation and is not an intermediate state between the solid and the liquid phase. The results suggest that the photo-excited state does not correspond to neither a warm nor a liquid phase, and open general questions on photoexcited phase transition.
Conference on Lasers and Electro-Optics 2012, 2012
ABSTRACT 800-nm pumped BIBO OPAs using Type-I and Type-II phase-matching are investigated and com... more ABSTRACT 800-nm pumped BIBO OPAs using Type-I and Type-II phase-matching are investigated and compared for achieving sub-50-fs pulses in the NIR. The OPAs achieve their shortest pulse durations of 19.8fs and 41.3fs, respectively, at 1.8μm.
Proceedings of the International Quantum Electronics Conference and Conference on Lasers and Electro-Optics Pacific Rim 2011, 2011
ABSTRACT Graphene presents many distinctive optical properties that complement its attractive ele... more ABSTRACT Graphene presents many distinctive optical properties that complement its attractive electronic and mechanical characteristics. We review some of the recent progress in understanding the electronic transitions and ultrafast dynamics in single and few-layer graphene crystals.
... J. Phys.: Condens. Matter , 18: 8195–8204. [CrossRef], [Web of Science ®] View all references... more ... J. Phys.: Condens. Matter , 18: 8195–8204. [CrossRef], [Web of Science ®] View all references,1919. Scotti di Uccio, U, Davidson, B, Di Capua, R, Miletto Granozio, F, Pepe, G, Perna, P, Ruotolo, A and Salluzzo, M. 2006. J. Alloys Compounds , 423: 228–231. ...
The study of photoexcited strongly correlated materials is attracting growing interest since thei... more The study of photoexcited strongly correlated materials is attracting growing interest since their rich phase diagram often translates into an equally rich out-of-equilibrium behaviour. With femtosecond optical pulses, electronic and lattice degrees of freedom can be transiently decoupled, giving the opportunity of stabilizing new states inaccessible by quasi-adiabatic pathways. Here we show that the prototype Mott–Hubbard material V2O3 presents a transient non-thermal phase developing immediately after ultrafast photoexcitation and lasting few picoseconds. For both the insulating and the metallic phase, the formation of the transient configuration is triggered by the excitation of electrons into the bonding a 1g orbital, and is then stabilized by a lattice distortion characterized by a hardening of the A 1g coherent phonon, in stark contrast with the softening observed upon heating. Our results show the importance of selective electron–lattice interplay for the ultrafast control of...
We report an experimental approach we used in order to time-resolve coherent optical phonon oscil... more We report an experimental approach we used in order to time-resolve coherent optical phonon oscillations in a bismuth (111) oriented bulk crystal by extreme ultraviolet (XUV) and soft x-ray femtosecond pulses based on high-order harmonic generation in rare gases.
2006 Conference on Lasers and Electro-Optics and 2006 Quantum Electronics and Laser Science Conference, 2006
1Laboratoire d'Optique Appliquée, ENSTA - Ecole Poly... more 1Laboratoire d'Optique Appliquée, ENSTA - Ecole Polytechnique, Chemin de la Hunière, 91761 Palaiseau, France 2Center for Ultrafast Optical Science, University of Michigan, 2200 Bonisteel Boulevard, Ann Arbor, MI 48109-2099, USA 3Applied Physics Department, University of Michigan, 2477 Randall Laboratory, Ann Arbor, MI 48109-1120, USA Email address: davide.boschetto@ensta.fr ... Abstract: We used Fresnel diffraction from knife-edges to demonstrate spatial coherence of ... In the recent years a significant effort has been put into the ...
2008 Conference on Lasers and Electro-Optics and 2008 Conference on Quantum Electronics and Laser Science, 2008
Time-resolved study of the dielectric function of femtosecond laser excited bismuth demonstrates ... more Time-resolved study of the dielectric function of femtosecond laser excited bismuth demonstrates that excitation of coherent phonons leads to a solid-plasma phase transition, and into a quasi-stable excited state lasting up to 4 ns.
ABSTRACT We present time-resolved dual-angle single-wavelength pump-probe study of the reflectivi... more ABSTRACT We present time-resolved dual-angle single-wavelength pump-probe study of the reflectivity of femtosecond laser excited bismuth crystal. The recovered real and imaginary parts of the dielectric function show complex a transition to a new quasi-stable excited state at about 20 ps. This state lasts for about 4 ns after the excitation and is not an intermediate state between the solid and the liquid phase. The results suggest that the photo-excited state does not correspond to neither a warm nor a liquid phase, and open general questions on photoexcited phase transition.
Conference on Lasers and Electro-Optics 2012, 2012
ABSTRACT 800-nm pumped BIBO OPAs using Type-I and Type-II phase-matching are investigated and com... more ABSTRACT 800-nm pumped BIBO OPAs using Type-I and Type-II phase-matching are investigated and compared for achieving sub-50-fs pulses in the NIR. The OPAs achieve their shortest pulse durations of 19.8fs and 41.3fs, respectively, at 1.8μm.
Proceedings of the International Quantum Electronics Conference and Conference on Lasers and Electro-Optics Pacific Rim 2011, 2011
ABSTRACT Graphene presents many distinctive optical properties that complement its attractive ele... more ABSTRACT Graphene presents many distinctive optical properties that complement its attractive electronic and mechanical characteristics. We review some of the recent progress in understanding the electronic transitions and ultrafast dynamics in single and few-layer graphene crystals.
... J. Phys.: Condens. Matter , 18: 8195–8204. [CrossRef], [Web of Science ®] View all references... more ... J. Phys.: Condens. Matter , 18: 8195–8204. [CrossRef], [Web of Science ®] View all references,1919. Scotti di Uccio, U, Davidson, B, Di Capua, R, Miletto Granozio, F, Pepe, G, Perna, P, Ruotolo, A and Salluzzo, M. 2006. J. Alloys Compounds , 423: 228–231. ...
The study of photoexcited strongly correlated materials is attracting growing interest since thei... more The study of photoexcited strongly correlated materials is attracting growing interest since their rich phase diagram often translates into an equally rich out-of-equilibrium behaviour. With femtosecond optical pulses, electronic and lattice degrees of freedom can be transiently decoupled, giving the opportunity of stabilizing new states inaccessible by quasi-adiabatic pathways. Here we show that the prototype Mott–Hubbard material V2O3 presents a transient non-thermal phase developing immediately after ultrafast photoexcitation and lasting few picoseconds. For both the insulating and the metallic phase, the formation of the transient configuration is triggered by the excitation of electrons into the bonding a 1g orbital, and is then stabilized by a lattice distortion characterized by a hardening of the A 1g coherent phonon, in stark contrast with the softening observed upon heating. Our results show the importance of selective electron–lattice interplay for the ultrafast control of...
We report an experimental approach we used in order to time-resolve coherent optical phonon oscil... more We report an experimental approach we used in order to time-resolve coherent optical phonon oscillations in a bismuth (111) oriented bulk crystal by extreme ultraviolet (XUV) and soft x-ray femtosecond pulses based on high-order harmonic generation in rare gases.
2006 Conference on Lasers and Electro-Optics and 2006 Quantum Electronics and Laser Science Conference, 2006
1Laboratoire d'Optique Appliquée, ENSTA - Ecole Poly... more 1Laboratoire d'Optique Appliquée, ENSTA - Ecole Polytechnique, Chemin de la Hunière, 91761 Palaiseau, France 2Center for Ultrafast Optical Science, University of Michigan, 2200 Bonisteel Boulevard, Ann Arbor, MI 48109-2099, USA 3Applied Physics Department, University of Michigan, 2477 Randall Laboratory, Ann Arbor, MI 48109-1120, USA Email address: davide.boschetto@ensta.fr ... Abstract: We used Fresnel diffraction from knife-edges to demonstrate spatial coherence of ... In the recent years a significant effort has been put into the ...
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