Atomically thin semiconductors hold great potential for nanoscale photonic and optoelectronic devices because of their strong light absorption and emission. Despite progress, their application in integrated photonics is hindered particularly by a lack of stable layered semiconductors emitting in the infrared part of the electromagnetic spectrum. Here we show that titanium trisulfide (TiS3), a layered van der Waals material consisting of quasi-1D chains, emits near infrared light centered around 0.91 eV (1360 nm). Its photoluminescence exhibits linear polarization anisotropy and an emission lifetime of 210 ps. At low temperature, we distinguish two spectral contributions with opposite linear polarizations attributed to excitons and defects. Moreover, the dependence on excitation power and temperature suggests that free and bound excitons dominate the excitonic emission at high and low temperatures, respectively. Our results demonstrate the promising properties of TiS3 as a stable semiconductor for optoelectronic and nanophotonic devices operating at telecommunication wavelengths.

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Broadband single photons are usually considered not to couple efficiently to atomic gases because of the large mismatch in bandwidth. Contrary to this intuitive picture, here we demonstrate that the interaction of ultrashort single photons with a dense resonant atomic sample deeply modifies the temporal shape of their wavepacket mode without degrading their non-classical character, and effectively generates zero-area single-photon pulses. This is a clear signature of strong transient coupling between single broadband (THz-level) light quanta and atoms, with intriguing fundamental implications and possible new applications to the storage of quantum information.Single photons are privileged carriers of quantum information because of their little interaction with the environment and among themselves. However, when it comes to storing and manipulating information, it would be useful for them to interact strongly with some atomic system in order to convert their quantum state into a stationary quantum state of matter [1]. Since atomic systems, either made of cold and ultracold atoms or of hot vapors, have absorption linewidths in the Hz to GHz range, the main road to enhance the atom-photon interaction has always been that of using sufficiently narrowband quantum photonic states, either produced in cavity-enhanced parametric down-conversion sources [2-5], or directly from cold [6][7][8][9] or hot [10, 11] atomic samples. In general, ultrashort single photons with bandwidths much broader than the atomic bandwidth are therefore not considered useful for this task because they are thought to interact only very weakly with the atoms. This is not necessarily true.Resonant interaction between ultrashort classical pulses and atomic media has long been investigated, together with some of its most peculiar effects. Two-photon transitions, for example, are well known to involve the whole bandwidth of an ultrashort pulse and to benefit considerably from the broad shaping of its spectral profile [12,13]. The formation of zero-area pulses is another spectacular consequence of the propagation of weak ultrashort pulses in the dispersive medium around an atomic resonance [14,15]. Considering a laser pulse whose description in frequency space is initially given by E(ω, 0), propagation through a distance l in the resonant medium modifies it to:where α 0 is the optical density of the medium, ω a is the atomic resonance frequency, and T 2 is the upper level lifetime. This approximate expression, which considers two-level atoms and an effective single lorentzian profile for the resonance line of the sample is enough to convey all the main features of the phenomenon. If the atomic transition is sufficiently narrow, the absorbed pulse energy can be almost negligible even in the case of high optical depths, but dispersion may still cause a dramatic re-shaping of the temporal pulse envelope. In accordance to the pulse area theorem [16][17][18], the electric field amplitude of the pulse rapidly develops a series of lobes of alternating signs ...

Quantum photonic integrated circuits hold great potential as a novel class of semiconductor technologies that exploit the evolution of a quantum state of light to manipulate information. Quantum dots encapsulated in photonic crystal structures are promising single-photon sources that can be integrated within these circuits. However, the unavoidable energy mismatch between distant cavities and dots, along with the difficulties in coupling to a waveguide network, has hampered the implementation of circuits manipulating single photons simultaneously generated by remote sources. Here we present a waveguide architecture that combines electromechanical actuation and Stark-tuning to reconfigure the state of distinct cavity-emitter nodes on a chip. The Purcell-enhancement from an electrically controlled exciton coupled to a ridge waveguide is reported. Besides, using this platform, we implement an integrated Hanbury-Twiss and Brown experiment with a source and a splitter on the same chip. These results open new avenues to scale the number of indistinguishable single photons produced on-demand by distinct emitters.

Quantum dots (QDs) interacting with confined light fields in photonic crystal cavities represent a scalable light source for the generation of single photons and laser radiation in the solid-state platform. The complete control of light-matter interaction in these sources is needed to fully exploit their potential, but it has been challenging due to the small length scales involved. In this work, we experimentally demonstrate the control of the radiative interaction between InAs QDs and one mode of three coupled nanocavities. By non-locally moulding the mode field experienced by the QDs inside one of the cavities, we are able to deterministically tune, and even inhibit, the spontaneous emission into the mode. The presented method will enable the real-time switching of Rabi oscillations, the shaping of the temporal waveform of single photons, and the implementation of unexplored nanolaser modulation schemes.