Molecular active plasmonics: controlling plasmon resonances with molecular machines
AuthorsZheng, Yue Bing
Juluri, Bala Krishna
Flood, Amar H.
Weiss, Paul S.
Stoddart, J. Fraser
Huang, Tony Jun
MetadataShow full item record
AbstractThe paper studies the molecular-level active control of localized surface plasmon resonances (LSPRs) of Au nanodisk arrays with molecular machines. Two types of molecular machines - azobenzene and rotaxane - have been demonstrated to enable the reversible tuning of the LSPRs via the controlled mechanical movements. Azobenzene molecules have the property of trans-cis photoisomerization and enable the photo-induced nematic (N)-isotropic (I) phase transition of the liquid crystals (LCs) that contain the molecules as dopant. The phase transition of the azobenzene-doped LCs causes the refractive-index difference of the LCs, resulting in the reversible peak shift of the LSPRs of the embedded Au nanodisks due to the sensitivity of the LSPRs to the disks' surroundings' refractive index. Au nanodisk array, coated with rotaxanes, switches its LSPRs reversibly when it is exposed to chemical oxidants and reductants alternatively. The correlation between the peak shift of the LSPRs and the chemically driven mechanical movement of rotaxanes is supported by control experiments and a time-dependent density functional theory (TDDFT)-based, microscopic model.
CitationZheng YB, Yang Y-W, Jensen L, Fang L, Juluri BK, et al. (2009) Molecular active plasmonics: controlling plasmon resonances with molecular machines. Plasmonics: Nanoimaging, Nanofabrication, and their Applications V. Available: http://dx.doi.org/10.1117/12.824525.
SponsorsWe thank Dr. Vincent Hsiao for his contribution to the experimental part of the azobenzene-based active tuning of the localized surface plasmon resonances, Dr. Amanda J. Haes for the MATHCAD code used in the Kramers−Kronig analysis, and Dr. Vincent Crespi for helpful discussions. This research was supported by the Air Force Office of Scientific Research (AFOSR), the National Science Foundation (NSF), and the Penn State Center for Nanoscale Science (an NSF-funded MRSEC). Components of this work were conducted at the Pennsylvania State University node of the NSF-funded National Nanotechnology Infrastructure Network. One of the authors (Y.B.Z.) thanks the support of a KAUST Scholar Award and the Founder’s Prize and Grant of the American Academy of Mechanics.
PublisherSPIE-Intl Soc Optical Eng
Conference/Event namePlasmonics: Nanoimaging, Nanofabrication, and their Applications V
CollectionsPublications Acknowledging KAUST Support
Showing items related by title, author, creator and subject.
Active Molecular Plasmonics: Controlling Plasmon Resonances with Molecular SwitchesZheng, Yue Bing; Yang, Ying-Wei; Jensen, Lasse; Fang, Lei; Juluri, Bala Krishna; Flood, Amar H.; Weiss, Paul S.; Stoddart, J. Fraser; Huang, Tony Jun (American Chemical Society (ACS), 2009-02-11)A gold nanodisk array, coated with bistable, redox-controllable rotaxane molecules, when exposed to chemical oxidants and reductants, undergoes switching of its plasmonic properties reversibly. By contrast, (i) bare gold nanodisks and (ii) disks coated with a redox-active, but mechanically inert, control compound do not display surface-plasmon-based switching. Along with calculations based on time-dependent density functional theory, these experimental observations suggest that the nanoscale movements within surface-bound “molecular machines” can be used as the active components in plasmonic devices.
Plasmonic Nanowires for Wide Wavelength Range Molecular SensingMarinaro, Giovanni; Das, Gobind; Giugni, Andrea; Allione, Marco; Torre, Bruno; Candeloro, Patrizio; Kosel, Jürgen; Di Fabrizio, Enzo M. (MDPI AG, 2018-05-17)In this paper, we propose the use of a standing nanowires array, constituted by plasmonic active gold wires grown on iron disks, and partially immersed in a supporting alumina matrix, for surface-enhanced Raman spectroscopy applications. The galvanic process was used to fabricate nanowires in pores of anodized alumina template, making this device cost-effective. This fabrication method allows for the selection of size, diameter, and spatial arrangement of nanowires. The proposed device, thanks to a detailed design analysis, demonstrates a broadband plasmonic enhancement effect useful for many standard excitation wavelengths in the visible and NIR. The trigonal pores arrangement gives an efficiency weakly dependent on polarization. The devices, tested with 633 and 830 nm laser lines, show a significant Raman enhancement factor, up to around 6 × 10⁴, with respect to the flat gold surface, used as a reference for the measurements of the investigated molecules.
Plasmonic metalens based on coupled resonators for focusing of surface plasmonsXu, Quan; Zhang, Xueqian; Xu, Yuehong; Li, Quan; Li, Yanfeng; Ouyang, Chunmei; Tian, Zhen; Gu, Jianqiang; Zhang, Wentao; Zhang, Xixiang; Han, Jiaguang; Zhang, Weili (Springer Nature, 2016-11-29)As an essential functionality, flexible focusing of surface plasmons (SPs) is of particular interest in nonlinear optics and highly integrated plasmonic circuitry. Here, we developed a versatile plasmonic metalens, a metasurface comprised of coupled subwavelength resonators, whose optical responses exhibit a remarkable feature of electromagnetically induced transparency (EIT). We demonstrate numerically and experimentally how a proper spatial design of the unit elements steers SPs to arbitrary foci based on the holographic principles. More specifically, we show how to control the interaction between the constituent EIT resonators to efficiently manipulate the focusing intensity of SPs. We also demonstrated that the proposed metalens is capable of achieving frequency division multiplexing. The power and simplicity of the proposed design would offer promising opportunities for practical plasmonic devices.