Ultranarrow Second-Harmonic Resonances in Hybrid Plasmon-Fiber Cavities

Ai Q, Gui L, Paone D, Metzger B, Mayer M, Weber K, Fery A, Giessen H (2018)

Publication Type: Journal article

Publication year: 2018

Journal

Nano Letters American Chemical Society

Book Volume: 18

Pages Range: 5576-5582

Journal Issue: 9

DOI: 10.1021/acs.nanolett.8b02005

Abstract

We demonstrate second-harmonic generation with ultranarrow resonances in hybrid plasmon-fiber cavities, formed by depositing single-crystalline gold nanorods onto the surface of tapered microfibers with diameters in the range of 1.7-1.8 μm. The localized surface plasmon mode of the single gold nanorod efficiently couples with a whispering gallery mode of the fiber, resulting in a very narrow hybrid plasmon-fiber resonance with a high quality factor Q of up to 250. When illuminated with a tunable 100 fs laser, a sharp SHG peak narrower than half of the spectral width of the impinging laser emerges, superimposed on a broad multiphoton photoluminescence background. The enhancement of the SHG peak of the hybrid system is typically 1000-fold when compared to that of a single gold nanorod alone. Tuning the laser over the hybrid resonance enables second-harmonic spectroscopy and yields an ultranarrow line width as small as 6.4 nm. We determine the second-harmonic signal to rise with the square of the laser power, while the multiphoton photoluminescence background rises with powers between 4 and 6, indicating a very efficient higher-order process. A coupled anharmonic oscillator model is able to describe the linear as well as second-harmonic resonances very well. Our work will open the door to the simultaneous utilization of narrow whispering gallery resonances together with high plasmonic near-field enhancement and should allow for nonlinear sensing and extremely efficient nonlinear light generation from ultrasmall volumes.

Involved external institutions

Universität Stuttgart DE Germany (DE) Leibniz-Institut für Polymerforschung Dresden e. V. DE Germany (DE)

How to cite

APA:

Ai, Q., Gui, L., Paone, D., Metzger, B., Mayer, M., Weber, K.,... Giessen, H. (2018). Ultranarrow Second-Harmonic Resonances in Hybrid Plasmon-Fiber Cavities. Nano Letters, 18(9), 5576-5582. https://doi.org/10.1021/acs.nanolett.8b02005

MLA:

Ai, Qi, et al. "Ultranarrow Second-Harmonic Resonances in Hybrid Plasmon-Fiber Cavities." Nano Letters 18.9 (2018): 5576-5582.

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