Search

Your search keyword '"CERULLO G"' showing total 18 results
Start Over Author "CERULLO G" Journal applied physics letters
18 results on '"CERULLO G"'

17. Observation of anomalous acoustic phonon dispersion in SrTiO3 by broadband stimulated Brillouin scattering.

Author

Brivio, S., Polli, D., Crespi, A., Osellame, R., Cerullo, G., and Bertacco, R.

Subjects
FEMTOSECOND lasers, PHONONS, BRILLOUIN scattering, TRANSITION metal oxides, PEROVSKITE, FERROMAGNETISM, FERROELECTRICITY, PIEZOELECTRICITY
Abstract

Femtosecond laser pulses have been used to generate and detect longitudinal acoustic phonons along the [001] direction of SrTiO3 single crystals coated with a thin absorbing layer. Two-dimensional maps of the reflectivity as a function of probe wavelength and time delay display persistent oscillations, from which the frequency-dependent group velocity of the photoinduced strain pulse can be directly measured. By applying the theory of stimulated Brillouin scattering we found that the longitudinal sound speed varies from 7900 to 7520 m/s in the 60-74 rad μm-1 wave vector range, thus indicating a clear deviation from a linear phonon dispersion relationship. [ABSTRACT FROM AUTHOR]

Published
2011
Full Text
View/download PDF

18. Femtosecond-irradiation-induced refractive-index changes and channel waveguiding in bulk Ti3+:Sapphire.

Author

Apostolopoulos, V., Laversenne, L., Colomb, T., Depeursinge, C., Salathé, R. P., Pollnau, M., Osellame, R., Cerullo, G., and Laporta, P.

Subjects
REFRACTIVE index, WAVEGUIDES, ELECTRIC waves, ELECTRICAL conductors, ELECTROMAGNETIC waves, HOLOGRAPHY, LASER recording
Abstract

We have employed femtosecond laser writing in order to induce refractive-index changes and waveguides in Ti3+-doped sapphire. Doping the sapphire crystal with an appropriate ion significantly reduces the threshold for creating structural changes, thus enabling the writing of waveguide structures. Passive and active buried channel waveguiding is demonstrated and images of the guided modes, propagation-loss values, fluorescence spectra, and output efficiencies are presented. The guiding area is located around the laser-damaged region, indicating that the guiding effect is stress induced. Refractive-index changes are measured by digital holography. Proper active doping should enable femtosecond processing and waveguide writing in various crystalline materials. [ABSTRACT FROM AUTHOR]

Published
2004
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results