NONLINEAR OPTICAL RESPONSE OF DOUBLY-RESONANT ALUMINUM NANOCLOCKS

Abdallah Slablab, Xiaorun Zang, Christian Ulysse, Giancarlo Rizza, Martti Kauranen

    Research output: Other conference contributionAbstractProfessional

    Abstract

    The down-sizing of the active medium to the nanoscale makes their nonlinear optical
    responses less efficient. To overcome this low efficiency at the nanoscale, plasmonenhanced
    nonlinear responses [1] using metallic nanoparticles have been proposed for
    nonlinear optics. The important aspect here is that the localized surface plasmon
    resonances (LSPRs) can concentrate incident light to strong local-fields (“hot spots”)
    near the metal-dielectric interfaces. This is clearly favourable for driving nonlinear
    optical responses, which scale with a high power of the optical field.
    In this context and as proposed previously [2], doubly-resonant structures are very
    promising for improving the nonlinear responses since they benefit from the field
    enhancement at both excitation and emission wavelengths. To meet this condition, the
    nanostructure or nanoparticle should be designed properly and the material well chosen.
    Here, we show numerically that double resonances can boost the second-harmonic
    generation (SHG) from a single aluminum (Al) nanoparticle. In order to avoid the
    limitations due to the oxidation, heating and dissipative effects in the most common
    plasmonic metals, e.g., gold and silver, recently Al has received wide interest as
    excellent material for plasmonics [3].
    We have studied both the linear and SHG responses of nanoclocks. A particle consists
    of a disk with two different extended arms attached (e.g., nanorods). This structure
    allows getting double resonances: one at the fundamental wavelength and the second at
    the SHG wavelength. The numerical study highlights a particular geometry (75 nm for
    the first arm and 35 nm for the second arm and a disk with diameter of 100 nm) with a
    suitable linear response (around 1060 nm and 530 nm). We also verified that the localfield
    distributions of at the fundamental and SHG wavelengths are spatially modematched
    allowing efficient SHG radiation into the far field. Finally, the scattering cross
    section for SHG was computed. Our results show that the SHG scattering is
    significantly enhanced compared to a singly resonant particle when the fundamental and
    SHG wavelengths coincide with the two plasmon resonances of the NC.
    [1] A. Kauranen and A. V. Zayats, Nature Photonics 6, 737 (2014).
    [2] M. Celebrano et al, Nature Nanotechnology 10, 412 (2015).
    [3] M. W. Knight et al, ACS Nano 8, 834 (2014).
    Original languageEnglish
    Number of pages1
    Publication statusPublished - 2017
    Eventphysics days 2017 - Aalto University Toolo Campus, Helsinki, Finland
    Duration: 22 Mar 201724 Mar 2017
    http://fp2017.physics.aalto.fi/

    Conference

    Conferencephysics days 2017
    Country/TerritoryFinland
    CityHelsinki
    Period22/03/1724/03/17
    Internet address

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