Enhancing the Nonlinear Optical Response Using Multifrequency Gold-Nanowire Antennas

Institute of Optics, University of Rochester, Rochester, New York 14627, USA.
Physical Review Letters (Impact Factor: 7.51). 05/2012; 108(21):217403. DOI: 10.1103/PhysRevLett.108.217403


We introduce and experimentally demonstrate the concept of multifrequency optical antennas that are designed for controlling the nonlinear response of materials. These antennas consist of two arms of different lengths, each resonant with one of the incoming frequencies. They are embedded in a nonlinear medium (indium tin oxide) that acts as a receiver. Because the two arms have different spectral resonances, tuning of the antenna gap size has minimal effect on the linear optical properties. However, it strongly affects the nonlinear response. Thus, by employing antenna elements with different spectral resonances, we provide a strategy to decouple the nonlinear response of nanomaterials from their linear optical properties.

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Available from: Hayk Harutyunyan, Oct 02, 2015
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    • "There are different strategies to enhance the optical nonlinear generation in nanostructures and metallic surfaces [6], [15] [16] [17] [18]. As in any nonlinear process, the signal strongly depends on the intensity of the input beams, and therefore the material must be tailored to obtain a large field enhancement at the fundamental frequencies. "
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    ABSTRACT: Optimizing the shape of nanostructures and nano antennas for specific optical properties has evolved to be a very fruitful activity. With modern fabrication tools a large variety of possibilities is available for shaping both nanoparticles and nanocavities; in particular nanocavities in thin metal films have emerged as attractive candidates for new metamaterials and strong linear and nonlinear optical systems. Here we rationally design metallic nanocavities to boost their Four Wave Mixing response by resonating the optical plasmonic resonances with the incoming and generated beams. The linear and nonlinear optical responses as well as the propagation of the electric fields inside the cavities are derived from the solution of Maxwell equations by using the 3D finite-differences time domain method. The observed conversion-efficiency of near infra-red to visible light equals or surpasses that of BBO of equivalent thickness. Implications to further optimization for efficient and broadband ultrathin nonlinear optical materials are discussed.
    Scientific Reports 12/2014; 5. DOI:10.1038/srep10033 · 5.58 Impact Factor
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    • "Concentration of electromagnetic radiation into nanometer-sized volumes is one of the major promises of plasmonics [1] [2]. Subwavelength focusing of energy is of enormous interest for many applications including coupling of light to single molecules [3] [4], field-enhanced spectroscopy and sensing [5] [6] [7] [8] [9], photochemistry [10], nonlinear frequency conversion [11] [12], and all-optical switching [13] [14] [15] [16]. In analogy with radiowave antennas, plasmonic nanoantennas are designed to optimize the coupling between far-field light and near-field 'hotspots' [5, 17– 19]. "
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    ABSTRACT: Plasmonic devices have a unique ability to concentrate and convert optical energy into a small volume. There is a tremendous interest in achieving active control of plasmon resonances, which would enable switchable hotspots for applications such as surface-enhanced spectroscopy and single molecule emission. The small footprint and strong-field confinement of plasmonic nanoantennas also holds great potential for achieving transistor-type devices for nanoscale-integrated circuits. To achieve such a functionality, new methods for nonlinear modulation are required, which are able to precisely tune the nonlinear interactions between resonant antenna elements. Here we demonstrate that resonant pumping of a nonlinear medium in a plasmonic hotspot produces an efficient transfer of optical Kerr nonlinearity between different elements of a multifrequency antenna. By spatially and spectrally separating excitation and readout, isolation of the hotspot-mediated ultrafast Kerr nonlinearity from slower, thermal effects is achieved.
    Nature Communications 09/2014; 5:4869. DOI:10.1038/ncomms5869 · 11.47 Impact Factor
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    • "[9] "
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    ABSTRACT: We study theoretically the cascaded four-wave mixing (FWM) in broadband tapered plasmonic nanoantennas and demonstrate a 300-fold increase in nonlinear frequency conversion detected in the main lobe of the nanoantenna far-field pattern. This is achieved by tuning the elements of the nanoantenna to resonate frequencies involved into the FWM interaction. Our findings have a potentially broad application in ultrafast nonlinear spectroscopy, sensing, on-chip optical frequency conversion, nonlinear optical metamaterials and photon sources.
    Optics Letters 01/2013; 38(1):79-81. DOI:10.1364/OL.38.000079 · 3.29 Impact Factor
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