：Room temperature strong coupling of WS 2 monolayer exciton transitions to metallic Fabry-Perot and plasmonic optical cavities is demonstrated. A Rabi splitting of 101 meV is observed for the Fabry-Perot cavity, more than double those reported to date in other 2D materials. The enhanced magnitude and visibility of WS 2 monolayer strong coupling is attributed to the larger absorption coefficient, the narrower linewidth of the A exciton transition, and greater spin-orbit coupling. For WS 2 coupled to plasmonic arrays, the Rabi splitting still reaches 60 meV despite the less favorable coupling conditions, and displays interesting photoluminescence features. The unambiguous signature of WS 2 monolayer strong coupling in easily fabricated metallic resonators at room temperature suggests many possibilities for combining light-matter hybridization with spin and valleytronics. induces the splitting of the excitonic transition by ca. 150 meV such that both the so-called A and B exciton transitions (see Figure 1b) can simultaneously interact with cavity modes complicating the studies of such systems. 27 The WS 2 monolayer has the advantage that it presents a much sharper isolated absorption band as can be seen in Figure 1b. In addition it displays an intense photoluminescence (PL) peak at 2.016 eV (Figure 1c). Hence WS 2 constitutes a natural choice for light-matter strong coupling. In this letter we demonstrate that by coupling WS 2 monolayers to metallic resonators, the magnitude and visibility of light-monolayer TMD strong coupling at room temperature is substantially enhanced with a Rabi splitting of 101 meV in Fabry-Perot cavities and 60 meV on plasmonic arrays. The energy-momentum dispersion properties of the monolayer WS 2 excitonpolaritons are explored by transmission, reflection and photoluminescence (PL) spectroscopy. In particular Rabi splittings in TE and TM dispersion curves give rise to unusual PL behavior. The results are discussed in terms of the potential of coherent light-matter interactions using WS 2 monolayers.To ensure high quality samples and to avoid environmental contamination, the TMD monolayers were exfoliated from bulk single crystals and then dry-transferred onto substrates as the holes possibly due to two factors: firstly, the plasmonic field has a maximum above the holes, enhancing the photonic mode density at this point, thereby increasing the excitonic radiative rate, 32 and secondly the increased dielectric screening where the monolayer is suspended over the hole rather than in Van der Waals contact with the substrate could enhance the emission. 10Angle-resolved transmission spectra of the FP cavity with WS 2 monolayer are shown in Figure 3a for TE polarization. The progressive dispersion of the cavity mode through the energy of the A exciton is accompanied by a clear anti-crossing, which is mapped out in terms of spectral maxima in Figure 3b. After fitting the energy of the two peaks as a function of in-plane momentum k // using the coupled oscillator model (described in the Met...

We demonstrate efficient generation of correlated photon pairs by spontaneous four wave mixing in a 5 μm radius silicon ring resonator in the telecom band around 1550 nm. By optically pumping our device with a 200 μW continuous wave laser, we obtain a pair generation rate of 0.2 MHz and demonstrate photon time correlations with a coincidence-to-accidental ratio as high as 250. The results are in good agreement with theoretical predictions and show the potential of silicon micro-ring resonators as room temperature sources for integrated quantum optics applications.

Entanglement is a fundamental resource in quantum information processing. Several studies have explored the integration of sources of entangled states on a silicon chip, but the devices demonstrated so far require millimeter lengths and pump powers of the order of hundreds of milliwatts to produce an appreciable photon flux, hindering their scalability and dense integration. Microring resonators have been shown to be efficient sources of photon pairs, but entangled state emission has never been proven in these devices. Here we report the first demonstration, to the best of our knowledge, of a microring resonator capable of emitting time-energy entangled photons. We use a Franson experiment to show a violation of Bell’s inequality by more than seven standard deviations with an internal pair generation exceeding 10⁷ Hz. The source is integrated on a silicon chip, operates at milliwatt and submilliwatt pump power, emits in the telecom band, and outputs into a photonic waveguide. These are all essential features of an entangled state emitter for a quantum photonic network

We demonstrate room temperature chiral coupling of valley excitons in a transition metal dichalcogenide monolayer with spin-momentum locked surface plasmons. At the onset of the strong coupling regime, we measure spin-selective excitation of directional flows of polaritons. Operating under such conditions, our platform yields surprisingly robust intervalley contrasts (ca. 40%) and coherence (ca. 5–8%) as opposed to their total absence for the uncoupled valley excitons at room temperature. These results open rich possibilities, easy to implement, in the context of chiral optical networks.