Quantum Optics with Photonic Nanowires and Photonic Trumpets: Basics and Applications

摘要

Optimizing the coupling between a localized quantum emitter and a single-mode optical channel represents a powerful route to realise bright sources of non-classical light states. Reversibly, the e±cient absorption of a photon impinging on the emitter is key to realise a spin-photon interface, the node of future quantum networks. Besides optical microcavities [1], photonic wires have recently demonstrated in this context an appealing potential [2, 3]. For instance, single photon sources (SPS) based on a single quantum dot in a vertical photonic wire with integrated bottom mirror and tapered tip have enabled for the ¯rst time to achieve simultaneously a very high e±ciency (0.72 photon per pulse) and a very pure single photon emission (g(2)(0) 0:01). Furthermore, photonic wires with an elongated cross-section provide polarization control of the spontaneous emission of embedded emitters [4]. However, the performance of photonic wire SPS with tapered tips is sensitive to minute geomet-rical details and optimum behaviour is only obtained for ultra-sharp tips. Photonic trumpets [5], which exploit the opposite tapering strategy, overcome this important limitation. Moreover, they feature a Gaussian far-¯eld emission, a strong asset for most applications. We report on the ¯rst implementation of this strategy and demonstrate an ultra-bright SPS (¯rst-lens external e±- ciency: 0:75 § 0:1) [5]. More generally, photonic trumpets appear as a very promising template to explore and exploit in a solid-state system the unique optical properties of one-dimensional atoms".