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.
Octave bandwidth photonic fishnet-achromatic-metalens
Planar structured interfaces, also known as metasurfaces, are continuously attracting interest owing to their ability to manipulate fundamental attributes of light, including angular momentum, phase, or polarization. However, chromatic aberration, limiting broadband operation, has remained a challenge for metasurfaces-based optical components and imagers. Here we report and experimentally demonstrate polarization-independent fishnet-achromatic-metalenses with measured average efficiencies over 70% in the continuous band from the visible (640 nm) to the infrared (1200 nm). Results of the scalable platform are enabling for applications requiring broad bandwidth and high efficiency including energy harvesting, virtual reality and information processing devices, or medical imaging.
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, J. Ha, J. Park, C. Chang-Hasnain, and B. Kanté, “Octave bandwidth photonic fishnet-achromatic-metalens,” Nature Communications 11, 3205 (2020).
- R. Contractor, W. Noh, Q. Le-Van, and B. Kanté, “Doping-induced plateau of strong electromagnetic confinement in the momentum space,” Optics Letters 45 (13) 3653–3656 (2020).
- 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).