Artículos de revistas
Investigation of the optical absorption of a magnetic colloid from the thermal to the electronic time-scale regime: measurement of the free-carrier absorption cross-section
Fecha
2012Registro en:
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B: OPTICAL PHYSICS, WASHINGTON, v. 29, n. 3, pp. 280-285, 2012
0740-3224
10.1364/JOSAB.29.000280
Autor
Espinosa, Daniel
Soga, Diogo
Alves, Sarah
De Boni, Leonardo
Zilio, Sergio Carlos
Figueiredo Neto, Antonio Martins
Institución
Resumen
The free-carrier absorption cross-section sigma of a magnetic colloid composed of magnetite nanoparticles dispersed in oil is obtained by using the Z-scan technique in different experimental conditions of the laser beam. We show that it is possible to obtain sigma with picosecond pulsed and millisecond chopped beams with pulse frequencies smaller than about 30 Hz. For higher pulse frequencies, the heating of the colloidal system triggers the appearance of the Soret effect. This effect artificially increases the value of sigma calculated from the experimental results. The limits of the different experimental setups are discussed. (C) 2012 Optical Society of America