Phonon polaritons (PhPs) in van der Waals (vdW) crystal slabs enable nanoscale infrared light manipulation. Specifically, periodically structured vdW slabs behave as polaritonic crystals (vdW-PCs), where the polaritons form Bloch modes. Because the polariton wavelengths are smaller than that of light, conventional far-field spectroscopy does not allow for a complete characterization of vdW-PCs or for revealing their band structure. Here, we perform hyperspectral infrared nanoimaging and analysis of PhPs in a vdW-PC slab made of h-BN. We demonstrate that infrared spectra recorded at individual spatial positions within the unit cell of the vdW-PC can be associated with its band structure and local density of photonic states (LDOS). We thus introduce hyperspectral infrared nanoimaging as a tool for the comprehensive analysis of polaritonic crystals, which could find applications in the reconstruction of complex polaritonic dispersion surfaces in momentum-frequency space or for exploring exotic electromagnetic modes in topological photonic structures.
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http://dx.doi.org/10.1021/acs.nanolett.1c01452 | DOI Listing |
Nanophotonics
January 2025
Departamento de Ingeniería Electrónica, E.T.S.I. de Telecomunicación, Instituto de Sistemas Optoelectrónicos y Microtecnología (ISOM), Universidad Politécnica de Madrid, Madrid, 28040 Spain.
Polar biaxial crystals with extreme anisotropy hold promise for the spatial control and the manipulation of polaritons, as they can undergo topological transitions. However, taking advantage of these unique properties for nanophotonic devices requires to find mechanisms to modulate dynamically the material response. Here, we present a study on the propagation of surface phonon polaritons (SPhPs) in a photonic architecture based on a thin layer of α-MoO deposited on a semiconducting 4H-SiC substrate, whose carrier density can be tuned through photoinduction.
View Article and Find Full Text PDFChem Commun (Camb)
January 2025
Research Institute for Electronic Science (RIES), Hokkaido University, N20W10, Kita ward, Hokkaido 001-0020, Japan.
Photochemical reactions enable the synthesis of energetically unfavorable compounds but often require irradiation with ultraviolet light, which potentially induces side reactions. Here, cavity strong coupling enhances the efficiency of an all-solid state photocyclization in crystals of 2,4-dimethoxy-β-nitrostyrene under irradiation with visible light. The exposure to visible light facilitates photocyclization by the transition to a lower polaritonic state, which is energetically lower than the original transition state.
View Article and Find Full Text PDFNano Lett
January 2025
Department of Physics, University of Oviedo, Oviedo 33006, Spain.
Polaritons are central to the development of nanophotonics, as they provide mechanisms for manipulating light at the nanoscale. A key advancement has been the demonstration of polariton canalization in which the energy flow is directed along a single direction. An intriguing case is the canalization of ray polaritons, characterized by an enhanced density of optical states.
View Article and Find Full Text PDFSci Adv
January 2025
State Key Laboratory of Extreme Photonics and Instrumentation, College of Optical Science and Engineering, International Research Center for Advanced Photonics, Zhejiang University, Hangzhou 310027, China.
Solution-processed semiconductor lasers are next-generation light sources for large-scale, bio-compatible and integrated photonics. However, overcoming their performance-cost trade-off to rival III-V laser functionalities is a long-standing challenge. Here, we demonstrate room-temperature continuous-wave perovskite polariton lasers exhibiting remarkably low thresholds of ~0.
View Article and Find Full Text PDFNano Lett
January 2025
State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, 100871 Beijing, China.
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