title: Modulation of the propagation speed of mechanical waves in silicon quantum dots embedded in a silicon-nitride film.
abstract: Using a vectorial picosecond self-diffraction method, we evaluate the modification of the speed of the sound in a silicon-nitride film containing silicon quantum dots prepared by remote plasma-enhanced chemical vapor deposition. Our non-contact technique is based on the stimulation of the electrostriction contribution to the nonlinearity of index exhibited by the sample in a multiwave mixing laser experiment. We identified the electronic birefringence using two of the incident beams to generate a self-diffraction signal, then, we modified the third order nonlinear response by means of the optical Kerr effect given by a phase-mismatched third beam which induced electrostriction. Our results indicated that the speed of the sound in a silicon-nitride film can be simultaneously tailored by an electronic nonlinear refractive index, and by an electrostriction effect, both resulting from silicon quantum dots doping.
authors.affiliation: Instituto de Física, Universidad Nacional Autónoma de México. México, D. F. 04510, México. crstorres@yahoo.com.mx
authors.forename: C
authors.initials: C
authors.lastname: Torres-Torres
authors.forename: A
authors.initials: A
authors.lastname: López-Suárez
authors.forename: R
authors.initials: R
authors.lastname: Torres-Martínez
authors.forename: A
authors.initials: A
authors.lastname: Rodriguez
authors.forename: J A
authors.initials: JA
authors.lastname: Reyes-Esqueda
authors.forename: L
authors.initials: L
authors.lastname: Castañeda
authors.forename: J C
authors.initials: JC
authors.lastname: Alonso
authors.forename: A
authors.initials: A
authors.lastname: Oliver