title: Ultrafast optical phase modulation with metallic nanoparticles in ion-implanted bilayer silica.
abstract: The nonlinear optical response of metallic-nanoparticle-containing composites was studied with picosecond and femtosecond pulses. Two different types of nanocomposites were prepared by an ion-implantation process, one containing Au nanoparticles (NPs) and the other Ag NPs. In order to measure the optical nonlinearities, we used a picosecond self-diffraction experiment and the femtosecond time-resolved optical Kerr gate technique. In both cases, electronic polarization and saturated absorption were identified as the physical mechanisms responsible for the picosecond third-order nonlinear response for a near-resonant 532 nm excitation. In contrast, a purely electronic nonlinearity was detected at 830 nm with non-resonant 80 fs pulses. Regarding the nonlinear optical refractive behavior, the Au nanocomposite presented a self-defocusing effect, while the Ag one presented the opposite, that is, a self-focusing response. But, when evaluating the simultaneous contributions when the samples are tested as a multilayer sample (silica-Au NPs-silica-Ag NPs-silica), we were able to obtain optical phase modulation of ultra-short laser pulses, as a result of a significant optical Kerr effect present in these nanocomposites. This allowed us to implement an ultrafast all-optical phase modulator device by using a combination of two different metallic ion-implanted silica samples. This control of the optical phase is a consequence of the separate excitation of the nonlinear refracting phenomena exhibited by the separate Au and Ag nanocomposites.
authors.affiliation: Sección de Estudios de Posgrado e Investigación, ESIME-Z, Instituto Politécnico Nacional, México, DF, Mexico. crstorres@yahoo.com.mx
authors.forename: C
authors.initials: C
authors.lastname: Torres-Torres
authors.forename: L
authors.initials: L
authors.lastname: Tamayo-Rivera
authors.forename: R
authors.initials: R
authors.lastname: Rangel-Rojo
authors.forename: R
authors.initials: R
authors.lastname: Torres-Martínez
authors.forename: H G
authors.initials: HG
authors.lastname: Silva-Pereyra
authors.forename: J A
authors.initials: JA
authors.lastname: Reyes-Esqueda
authors.forename: L
authors.initials: L
authors.lastname: Rodríguez-Fernández
authors.forename: A
authors.initials: A
authors.lastname: Crespo-Sosa
authors.forename: J C
authors.initials: JC
authors.lastname: Cheang-Wong
authors.forename: A
authors.initials: A
authors.lastname: Oliver