Modulation of the propagation speed of mechanical waves in silicon quantum dots embedded in a silicon-nitride film

• Published in: Optics express Vol. 20; no. 4; pp. 4784 - 4789
• Main Authors: Torres-Torres, C, López-Suárez, A, Torres-Martínez, R, Rodriguez, A, Reyes-Esqueda, J A, Castañeda, L, Alonso, J C, Oliver, A
• Format: Journal Article
• Language: English
• Published: United States 13-02-2012
• ISSN: 1094-4087; 1094-4087
• DOI: 10.1364/OE.20.004784

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.