Abstract
Optical conduction resonance- (OCR-) enhanced third-order optical nonlinearity of two dimensional (2D) periodic gold nanoparticle array-dielectric thin films has been investigated. The third-order optical susceptibility of periodic gold nanoparticle array embedded in silica thin film shows ~104 enhancement comparing to gold nanoparticle colloids. The 2D gold nanoparticle arrays were synthesized by using the electrostatic self-assembly (ESA) technique. During the fabrication process, the positively or negatively functionalized gold nanoparticles are automatically self-aligned to establish a 2D array with a very small interparticle spacing due to the polymer shell on the metal particles. Then, a monolayer of silica can be coated on the top of the 2D metal nanoparticle array. This type of 2D gold nanoparticle array-dielectric thin films has high volume fraction of gold nanoparticles. According to the extended Maxwell-Garnett theory, this kind of films can exhibit OCR. The OCR frequency can be tuned from visible to mid-infrared by controlling the gold nanoparticle volume fraction. During OCR, the real part of the composite dielectric constant is zero to make the induced electromagnetic waves in gold nanoparticles to couple effectively within the film. The open-aperture z-scan technique is used to measure the nonlinear optical properties of the ESA films.
Highlights
Gold (Au) nanoparticles and clusters are known to possess a fast and extremely large nonlinear optical susceptibility [1, 2]
Au nanoparticles have strong nonlinear optical susceptibility; their optical properties are highly sensitive to interparticle distance [24, 53]
In regular Au nanoparticle colloids, the particle volume fraction is very low and the interparticle distance can change dramatically. This may be used to interpret why Au colloids cannot show very large third-order optical susceptibility
Summary
Gold (Au) nanoparticles and clusters are known to possess a fast and extremely large nonlinear optical susceptibility (third-order susceptibility of χ 3 can be as much as 106 times larger than that of the standard reference of CS2) [1, 2]. The experimental investigation of nonlinear optical phenomena in Au nanoparticle-incorporated systems started in the 1980s [6,7,8], most of the research work is concentrated on low metal particle volume fraction. Some questions on the exact origin of the enhanced nonlinear optical susceptibility still remain [20, 26], it is generally agreed that closely ordered periodic metal nanostructures and aggregated nanometal clusters can provide a large local-field enhancement because of small interparticle spacing and collective oscillation of conduction electron gas [12,13,14,15] that is called OCR. This work reports using the electrostatic self-assembly (ESA) technique to fabricate two-dimensional (2D) Au nanoparticle arraydielectric thin films containing high volume fraction of Au nanoparticles to investigate this type of resonance through theoretical calculations and experimental characterizations. The measured results of third-order susceptibility from the thin films containing high-volume Au particles will be shown
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
