Gigahertz Detection Rates and Dynamic Photon-Number Resolution with Superconducting Nanowire Arrays.

Superconducting nanowire single-photon detectors (SNSPDs) have enabled the realization of several quantum optics technologies thanks to their high system detection efficiency (SDE), low dark counts, and fast recovery time. However, the widespread use of linear optical quantum computing, quasi-deterministic single-photon sources, and quantum repeaters requires even faster detectors that can also distinguish between different photon-number states. Here, we present an SNSPD array composed of 14 independent pixels, achieving an SDE of 90% in the telecommunications band.

Shallow- and Deep-Water Species Produce a Panel of Chlorin Compounds with Potent Photodynamic Anticancer Activities.

A Pacific brittle star has previously been shown to produce a chlorin (3,4)-14-Ethyl-9-(hydroxymethyl)-4,8,13,18-tetramethyl-20-oxo-3-phorbinepropanoic acid (ETPA) () with potent phototoxic activities, making it applicable to photodynamic therapy. Using extensive LC-MS metabolite profiling, molecular network analysis, and targeted isolation with de novo NMR structure elucidation, we herein identify five additional chlorin compounds from and its deep-sea relative : 10S-Hydroxypheophorbide a (), Pheophorbide a (), Pyropheophorbide a (), (3,4,21)-14-Ethyl-9-(hydroxymethyl)-21-(methoxycarbonyl)-4,8,13,18-tetramethyl-20-oxo-3-phorbinepropanoic acid (), and (3,4,21)-14-Ethyl-21-hydroxy-9-(hydroxymethyl)-4,8,13,18-tetramethyl-20-oxo-3-phorbinepropanoic acid (). Chlorins and have not been previously reported in natural sources.

High-rate photon pairs and sequential Time-Bin entanglement with SiN microring resonators.

Integrated photonics is increasing in importance for compact, robust, and scalable enabling quantum technologies. This is particularly interesting for developing quantum communication networks, where resources need to be deployed in the field. We exploit photonic chip-based SiN microring resonators to realise a photon pair source with low-loss, high-noise suppression and coincidence rates of 80×10 s.

Heralded amplification of photonic qubits.

We demonstrate postselection free heralded qubit amplification for Time-Bin qubits and single photon states in an all-fibre, telecom-wavelength, scheme that highlights the simplicity, stability and potential for fully integrated photonic solutions. Exploiting high-efficiency superconducting detectors, the gain, fidelity and the performance of the amplifier are studied as a function of loss. We also demonstrate the first heralded single photon amplifier with independent sources.

Demonstration of Quantum Nonlocality in the Presence of Measurement Dependence.

Quantum nonlocality stands as a resource for device independent quantum information processing (DIQIP), such as, for instance, device independent quantum key distribution. We investigate, experimentally, the assumption of limited measurement dependence, i.e.

MHz rate and efficient synchronous heralding of single photons at telecom wavelengths.

We report on the realization of a synchronous source of heralded single photons at telecom wavelengths with MHz heralding rates and high heralding efficiency. This source is based on the generation of photon pairs at 810 and 1550 nm via Spontaneous Parametric Down Conversion (SPDC) in a 1 cm periodically poled lithium niobate (PPLN) crystal pumped by a 532 nm pulsed laser. As high rates are fundamental for multi-photon experiments, we show that single telecom photons can be announced at 4.

Faithful entanglement swapping based on sum-frequency generation.

We show that an entanglement swapping operation performed with spontaneous parametric down-conversion can be made faithful without postselection using sum-frequency generation. This invites us to revisit the sum-frequency process and from a proof-of-principle experiment, we demonstrate that it provides a realistic solution for nonlinear optics at the single-photon level. This opens the way to attractive alternatives to six-photon protocols based on linear optics used, e.

32 bin near-infrared time-multiplexing detector with attojoule single-shot energy resolution.

We present two implementations of photon counting time-multiplexing detectors for near-infrared wavelengths, based on Peltier cooled InGaAs/InP avalanche photodiodes. A first implementation is motivated by practical considerations using only commercially available components. It features 16 bins, pulse repetition rates of up to 22 kHz, and a large range of applicable pulse widths of up to 100 ns.

Coherent frequency-down-conversion interface for quantum repeaters.

We report a coherence-preserving photon frequency down-conversion experiment based on difference-frequency generation in a periodically poled Lithium niobate waveguide, at the single-photon level. The coherence of the process has been demonstrated by measuring the phase coherence of pseudo single-photon time-bin qubits after frequency conversion with an interference visibility of >96 %. This interface could be of interest for quantum repeater based hybrid networks.

Room temperature photon number resolving detector for infared wavelengths.

In this paper we present a photon number resolving detector at infrared wavelengths, operating at room temperature and with a large dynamic range. It is based on the up-conversion of a signal at 1559 nm into visible wavelength and on its detection by a thermoelectrically cooled multi-pixel silicon avalanche photodiodode, also known as a Silicon Photon Multiplier. With the appropriate up-conversion this scheme can be implemented for arbitrary wavelengths above the visible spectral window.

Continuous high speed coherent one-way quantum key distribution.

Quantum key distribution (QKD) is the first commercial quantum technology operating at the level of single quanta and is a leading light for quantum-enabled photonic technologies. However, controlling these quantum optical systems in real world environments presents significant challenges. For the first time, we have brought together three key concepts for future QKD systems: a simple high-speed protocol; high performance detection; and integration both, at the component level and for standard fibre network connectivity.

High resolution optical time domain reflectometer based on 1.55mum up-conversion photon-counting module.

We implement a photon-counting Optical Time Domain Reflectometer (OTDR) at 1.55mum which exhibits a high 2-point resolution and a high accuracy. It is based on a low temporal-jitter photon-counting module at 1.