Plasmonic nanolasers (spasers) are of intense interest, attributable to their ability to generate a high-intensity coherent radiation. We infiltrated a three-dimensional silica-based photonic crystal (PhC) film with spasers, composed of spherical gold cores, surrounded by silica shells with dye molecules. In spasers, the gold nanospheres supported the surface plasmons and the dye molecules transferred incoming optical energy to the surface plasmons. Our experiments show that such a structure, consisting of a PhC, which acts as an external distributed feedback resonator, and spasers, can serve as a coherent source of electromagnetic radiation. Spasers were locked in phase by the common radiation causing a phenomenon called the lasing spaser: the emission of spatially and temporarily coherent light normal to the surface of the PhC film. The far-field radiation patterns appeared in the shape of the Star-of-David, which is due to the dispersion along the Brillouin zone boundary. The infiltration of the spasers into the PhC led to drastic narrowing of the emission peak and an 80-fold decrease in the spaser generation threshold with respect to the same spasers in a suspension at room temperature.
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http://dx.doi.org/10.1021/acsomega.0c05813 | DOI Listing |
Nanomaterials (Basel)
May 2021
Department of Optics and Quantum Electronics, University of Szeged, Dóm tér 9, 6720 Szeged, Hungary.
Plasmonic nanoresonators consisting of a gold nanorod and a spherical silica core and gold shell, both coated with a gain layer, were optimized to maximize the stimulated emission in the near-field (NF-c-type) and the outcoupling into the far-field (FF-c-type) and to enter into the spasing operation region (NF-c*-type). It was shown that in the case of a moderate dye concentration, the nanorod has more advantages: smaller lasing threshold and larger slope efficiency and larger achieved intensities in the near-field in addition to FF-c-type systems' smaller gain and outflow threshold, earlier dip-to-peak switching in the spectrum and slightly larger far-field outcoupling efficiency. However, the near-field (far-field) bandwidth is smaller for NF-c-type (FF-c-type) core-shell nanoresonators.
View Article and Find Full Text PDFACS Nano
June 2021
Optical Materials Engineering Laboratory, Department of Mechanical and Process Engineering, ETH Zurich, 8092 Zurich, Switzerland.
Plasmonic modes in optical cavities can be amplified through stimulated emission. Using this effect, plasmonic lasers can potentially provide chip-integrated sources of coherent surface plasmon polaritons (SPPs). However, while plasmonic lasers have been experimentally demonstrated, they have not generated propagating plasmons as their primary output signal.
View Article and Find Full Text PDFACS Omega
February 2021
Center for Nano-Optics (CeNO) and Department of Physics and Astronomy, Georgia State University, 29 Peachtree Center Avenue, Atlanta, Georgia 30303-4106, United States.
Plasmonic nanolasers (spasers) are of intense interest, attributable to their ability to generate a high-intensity coherent radiation. We infiltrated a three-dimensional silica-based photonic crystal (PhC) film with spasers, composed of spherical gold cores, surrounded by silica shells with dye molecules. In spasers, the gold nanospheres supported the surface plasmons and the dye molecules transferred incoming optical energy to the surface plasmons.
View Article and Find Full Text PDFLight Sci Appl
May 2020
Nanoscale Science and Engineering Center, University of California, Berkeley, Berkeley, CA 94720 USA.
To construct a dielectric analog of a spaser, we study several configurations of cluster-based unit cells for an all-dielectric metasurface characterized by resonant conditions of the trapped mode excitation. Excitation of the trapped mode is realized by performing either specific displacement of particles in the cluster or perturbation of the equidistantly spaced particles by off-centered holes. The latter approach is more advantageous for enhancement of the electric near-field with homogeneous distribution in-plane of the structure and strong field localization outside the high-refractive-index dielectric particles.
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