We are dedicated to multidisciplinary research in the area of wave-matter interaction from microwaves to optics. Grounded on the fundamental physical principles, and the on-demand dimensionality of materials and nanomaterials, we address tantalizing experimental and theoretical physical questions in the fields of nanophotonics, plasmonics, and metamaterials applicable to global energy, defense, and health challenges.
Symmetry-breaking-induced plasmonic exceptional points and nanoscale sensing
Singularities of open systems, known as exceptional points (EPs), have been shown to exhibit increased sensitivities, but the observation of EPs has so far been limited to wavelength-scaled systems subject to the diffraction limit. We propose a novel approach to EPs based on spatial symmetry breaking and report their observation in plasmonics at room temperature. Their utility as sensors of anti-immunoglobulin G, the most abundant immunoglobulin isotype in human serum, is evaluated. Our work opens the way to a new class of nanoscale devices, sensors and imagers based on topological polaritonic effects.
Nonreciprocal lasing in topological cavities of arbitrary geometries
Resonant cavities that confine light are crucial components of lasers. Typically, these cavities are designed to high specification to get the best possible output. That, however, can limit their integration into photonic devices and optical circuits. The confinement of light to topologically protected edge states can result in unidirectional propagation and confinement over arbitrary geometries. Relaxing the resonant cavity design criteria should be useful in designing photonic devices.
Lasing action from photonic bound states in continuum
In 1929, only three years after the advent of quantum mechanics, von Neumann and Wigner showed that Schrödinger’s equation can have bound states above the continuum threshold. These peculiar states, called bound states in the continuum (BICs), manifest themselves as resonances that do not decay. Here we report, at room temperature, lasing action from an optically pumped BIC cavity. BIC lasers open up new avenues in the study of light–matter interaction because they are intrinsically connected to topological charges and represent natural vector beam sources which are highly sought after in the fields of optical trapping, biological sensing and quantum information.
- A. Ndao, L. Hsu, W. Cai, J. Ha, J. Park, R. Contractor, Y. Lo, and B. Kanté, “Differentiating and quantifying exosome secretion from a single cell using quasi-bound states in the continuum,” Nanophotonics (published online ahead of print), 20200008 (2020).
- J. Park*, A. Ndao*, W. Cai, L.-Y. Hsu, A. Kodigala, T. Lepetit, Y.-H. Low, and B. Kanté “Symmetry-breaking-induced plasmonic exceptional points and nanoscale sensing,” Nature Physics 16 (4), 462–468 (2020).
- Y. Ota, K. Takata, T. Ozawa, A. Amo, Z. Jia, B. Kanté, M. Notomi, Y. Arakawa, and S. Iwamoto, “Active topological photonics,” Nanophotonics, 9 (3), 547–567 (2020).
- C.-Y. Fang, S. H. Pan, F. Vallini, A. Tukiainen, J. Lyytikäinen, G. Nylund, B. Kanté, M. Guina, A. El Amili, and Y. Fainman, “Lasing action in low-resistance nanolasers based on tunnel junctions,” Optics Letters 44 (15), 3669–3672 (2019).
- L.-Y. Hsu, A. Ndao, and B. Kanté, “Broadband and linear polarization metasurface carpet cloak in the visible,” Optics Letters 44 (12), 2978–2981 (2019).
- W. Noh, M. Dupré, A. Ndao, A. Kodigala, B. Kanté, “Self-Suspended Microdisk Lasers with Mode Selectivity by Manipulating the Spatial Symmetry of Whispering Gallery Modes,” ACS Photonics 6 (2), 389–394 (2019).