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Band engineering stands as an efficient route to induce strongly correlated quantum many-body phenomena. Besides inspiring analogies among diverse physical fields, tuning on demand the group velocity is highly attractive in photonics because it allows unconventional flows of light. $\Lambda$-schemes offer a route to control the propagation of light in a lattice-free configurations, enabling exotic phases such as slow-light and allowing for highly optical non-linear systems. Here, we realize room-temperature intercavity Frenkel polaritons excited across two strongly coupled cavities. We demonstrate the formation of a tuneable heavy-polariton, akin to slow light, appearing in the absence of a periodic in-plane potential. Our photonic architecture based on a simple three-level scheme enables the unique spatial segregation of photons and excitons in different cavities and maintains a balanced degree of mixing between them. This unveils a dynamical competition between many-body scattering processes and the underlying polariton nature which leads to an increased fluorescence lifetime. The intercavity polariton features are further revealed under appropriate resonant pumping, where we observe suppression of the polariton fluorescence intensity., Comment: 8+ 4 pages

Frenkel polaritons, hybrid light-matter quasiparticles, offer promises for the designing of new opto-electronic devices. However, their technological implementations are hindered by sensitivity to imperfections. Topology has raised as a way to circumvent defects and fabrication limitations. Here, we propose a lattice of cavities to realize the one-dimensional Su-Schrieffer-Heeger model (SSH) for topological Frenkel polaritons. By engineering the configuration of the cavities we demonstrate that the SSH topological and trivial phases can be accessed, which we unravel by complementary classical and quantum theories. We demonstrate the polariton edge state robustness under defects and the broadening of the photon and exciton lines. Our findings propose a realistic yet simple experimental setup to realize topological room temperature polaritons., Comment: 9 pages and 9 figures

Organic polaritons resulting from the strong hybridisation between photons and matter excitations have arisen as a suitable platform to device light-matter technological interfaces at room temperature. Despite their inherent complexity, organic polaritons are commonly regarded as coherent light-matter excitations that can be described in terms of Landau's quasiparticle approach. Here, we experimentally unveil the role of incoherent matter excitations on the polaritons by exploring the relevant energy-momentum parameter space. We demonstrate the emergence of a well-defined lower polariton branch and an intriguing fading of the upper polariton at its entrance to a continuum of matter excitations. This marks the breakdown of the simplistic quasiparticle picture for this branch and the formation of a more complex quantum state. Our experimental results are sustained by a general theoretical framework that allows understanding the light-matter hybridisation beyond the quasiparticle approach. Our work expands the understanding of organic polaritons in all their complexity and increases their technological significance., Comment: 4+4 pages, 3 +1 figures

This paper presents the development of scientific instrumentation for the fabrication of ferromagnetic thin films, by sputtering technique, for the use of 2-inch-diameter targets. Thin films were deposited using Permalloy alloy (Ni80Fe20) as ferromagnetic material at room temperature on Si (001) substrates. The film thicknesses were measured with profilometry and a deposition rate for this alloy of 16.2 nm/min was calculated. Scanning electron microscopy showed a continuous film formation and a chemical composition similar to the target, Comment: 7 pages, in Spanish, 8 figures, 1 table

We present a theoretical study of the modification of the near-field radiative heat transfer due to phonon-plasmon coupling in bilayer systems made of a doped semiconductor and a polar dielectric. By tuning the surface-plasmon mode of the former material in resonance with the phonon modes of the latter one, the near-field spectral radiative heat transfer can be suppressed in a frequency band gap. We distinguish between the interlayer mode coupling within each bilayer and the intragap one between the two bilayers. We elucidate the role of each of them in the formation of the band gap and we determine the distance range at which one mechanism dominates over the other. Furthermore, we show that the surface plasmon polariton of the top-most layer allows optimizing the total heat transfer as a function of the separation of the two bilayers., Comment: 5 figures

We show the existence of Fano resonances in the context of near-field radiative heat transfer, which enable the strong suppression and enhancement of the spectral heat flux at specific wavelengths. This is demonstrated by making use of the plasmon-phonon coupling in a symmetric nano cavity composed by a polaritonic material coated with a metallic layer, in which each side of the cavity is kept at different temperatures. The strong hybridization of the plasmonic and phononic modes sustained by the multilayer structure is determined by the matching of their polarization. This leads to the opening of a thermal band gap, where heat transfer in the coupled system is inhibited for all wave vectors and for wavelengths at which the individual constituents are thermally transmissive., Comment: 4 figures

We experimentally demonstrate the coherent control, i.e., phase-dependent enhancement and suppression, of the optical absorption in an array of metallic nanoantennas covered by a thin lu- minescent layer. The coherent control is achieved by using two collinear, counter-propagating and phase-controlled incident waves with wavelength matching the absorption spectrum of dye molecules coupled to the array. Symmetry arguments shed light on the relation between the relative phase of the incident waves and the excitation efficiency of the optical resonances of the system. This coherent control is associated with a phase-dependent distribution of the electromagnetic near-fields in the structure which enables a significant reduction of the unwanted dissipation in the metallic structures., Comment: 4 pages, 4 figures

We demonstrate a large light absorptance (80%) in a nanometric layer of quantum dots in rods (QRs) with a thickness of 23 nm. This behavior is explained in terms of the coherent absorption by interference of the light incident at a certain angle onto the very thin QR layer. We exploit this coherent light absorption to enhance the photoluminescent emission from the QRs. Up to a seven- and fivefold enhancement of the photoluminescence is observed for p- and s-polarized incident light, respectively., Comment: Physical Review B 2012

We describe both theoretically and experimentally the existence and excitation of confined modes in planar arrays of gold nanodisks. Ordered 2D lattices of monodispersive nanoparticles are manufactured, embedded in a silica matrix, and exposed to evanescent prism-coupling illumination, leading to dark features in the reflectivity, which signal the presence of confined modes guided along the arrays. We find remarkable agreement between theory and experiment in the frequency-momentum dispersion of the resonances. Direct excitation of these modes reveals long propagation distances and deep extinction features. This characterization of guided modes shows the great potential of metallic particle arrays for optical signal processing and distant sensing applications.