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Nano-IR imaging of phonon polaritons in hyperbolic strutures at cryogenic temperatures. a, Table with properties of examined hyperbolic materials b, Sketch of the layered Au/hBN and -MoO3/Au structures. The lithographically-defined gold (Au) microstructures on top of the hBN (or below the -MoO3) serve as effective plasmonic launchers. c, Nanoscale infrared image of phonon polariton fringes from the Au/h 11 BN, expressed by the normalized scattering amplitude s acquired at a temperature of T = 50 K. The arrows represent the propagation
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Natural hyperbolic materials with dielectric permittivities of opposite sign along different principal axes can confine long-wavelength electromagnetic waves down to the nanoscale, well below the diffraction limit. This has been demonstrated using hyperbolic phonon polaritons (HPP) in hexagonal boron nitride (hBN) and -MoO3, among other materials....
Contexts in source publication
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... avoid the complications of p and p/2 fringe decompositions, an alternative approach is preferred. In our device (Figs.1b), pre-patterned micron-sized Au disk structures residing on top of the hBN crystals (bottom of -MoO3), serve as fixed HPP antennas (Figs. ...
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... in the imaging of coexisting fringes with two distinct periodicities p and p/2. To avoid the complications of p and p/2 fringe decompositions, an alternative approach is preferred. In our device (Figs.1b), pre-patterned micron-sized Au disk structures residing on top of the hBN crystals (bottom of -MoO3), serve as fixed HPP antennas (Figs. 1,2) predominantly producing fringes with p periodicity. of the plasmon waves. These experiments simultaneously visualize the local electric field associated with interference fringe patterns from phonon polaritons emitted by the Au ...
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... begin with a survey of a large-area (25 20 m 2 ) image of HPP standing waves in h 11 BN obtained at T = 50 K (Fig. 1c) with an IR laser operating at IR = 6.6 m. Here we display raw data in the form of the scattered near-field amplitude s normalized to the corresponding signal detected from the gold disks, whose optical response provides a convenient temperature (T)-independent reference. The most prominent aspect of the image in Fig. 1c is that the ...
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... obtained at T = 50 K (Fig. 1c) with an IR laser operating at IR = 6.6 m. Here we display raw data in the form of the scattered near-field amplitude s normalized to the corresponding signal detected from the gold disks, whose optical response provides a convenient temperature (T)-independent reference. The most prominent aspect of the image in Fig. 1c is that the entire field of view is filled with HPP fringes. As expected, the p-fringes dominate the field of view, emanating from the Au antenna and propagating radially outwards. Even a cursory inspection of Fig. 1c reveals that HPP remain highly confined with IR/p > 20 and yet they travel over tens of microns, far exceeding ...
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... whose optical response provides a convenient temperature (T)-independent reference. The most prominent aspect of the image in Fig. 1c is that the entire field of view is filled with HPP fringes. As expected, the p-fringes dominate the field of view, emanating from the Au antenna and propagating radially outwards. Even a cursory inspection of Fig. 1c reveals that HPP remain highly confined with IR/p > 20 and yet they travel over tens of microns, far exceeding previous measurements at ambient temperature 6,13 ...
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