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An ‘all-optical’ technique is proposed that can be used to detect broadband terahertz waves by coherently manipulating fluorescence emission from a gas plasma. This technique can be used to measure terahertz pulses at a distance of 10 m with unlimited directionality, even in the presence of water vapour absorption.
Researchers present the first heralded generation of photon states that are maximally entangled in polarization with linear optics. Three photon pairs are generated by spontaneous parametric down-conversion from β-barium borate crystals. The coincident detection of four auxiliary photons unambiguously heralds the successful preparation of the entangled state.
The phase locking of a longitudinal mode of a 2.7 THz quantum cascade laser was achieved using the spectral bandwidth of a mode-locked erbium-doped fibre laser. This technique is applicable to any terahertz quantum cascade laser source, and is an ideal tool for controlling the phase of different quantum cascade lasers.
Researchers demonstrate coherent control of an exciton qubit in a semiconductor quantum dot through optoelectronic means. Such state manipulation of single quantum systems is essential for the development of quantum information systems.
Long-range surface plasmon propagation with net positive gain over macroscopic distances is directly observed. The gain is provided by an optically pumped layer of fluorescent conjugated polymer that is adjacent to the metal waveguide surface.
An efficient source of entangled photons generated in an event-ready manner by conditioned detection of auxiliary photons is reported. A fidelity better than 87% and a state preparation efficiency of 45% are obtained. The scheme could offer promising applications in essential photonics-based quantum information tasks, and represents a particularly important development in the realization of optical quantum computing.
Using probe and pump waves derived from ultra-compact telecom optical fibre sources, scientists perform four-wave mixing in silicon waveguides in the spectral region beyond 2 µm, achieving mid-infrared wavelength generation of 2388 nm over a bandwidth of 630 nm on a silicon chip.
By taking advantage of the absorption reduction at wavelengths approaching the two-photon absorption bandedge of 2,200 nm, scientists demonstrate a mid-infrared silicon optical parametric amplifier that exhibits broadband gain as large as 25.4 dB and a net off-chip amplification of 13 dB using only an ultra-compact 4-mm silicon chip.
Researchers demonstrate free-space quantum teleportation through 16 kilometres of air. The results may pave the way for space-based experiments and global scale quantum communication applications.
Scientists demonstrate a simple self-referenced feed-forward approach for stabilizing the carrier–envelope phase of femtosecond light pulses. Twelve attoseconds of residual timing jitter below the atomic unit of time is achieved, surpassing the precision of previous methods by more than a factor of five.
Microscale planar optical elements based on high-reflectivity, non-periodic gratings provide a compact and convenient means for focusing and shaping light.
Using a composite photonic-crystal structure composed of both a square and rectangular lattice, scientists successfully realize an on-chip semiconductor laser whose emitted beams can be dynamically controlled by varying their relative lattice constants.
Water condensation from air using intense, ultrashort laser pulses is demonstrated, an approach that could benefit remote sensing and studies in atmospheric science.
An ultrafast, all-optical spin echo technique is used to increase the decoherence time of a single quantum dot electron spin from nanoseconds to several microseconds. The ratio of decoherence time to gate time exceeds 105, suggesting strong promise for future photonic quantum information processors and repeater networks.
Polaritons in organic semiconductors are highly stable at room temperature, but so far nonlinear emission from these structures has not been demonstrated. Here, polariton lasing at room temperature in an organic microcavity composed of a melt-grown anthracene single crystal sandwiched between two dielectric mirrors is reported.
An all-optical spin switch based on exciton–polaritons in a semiconductor microcavity is demonstrated. These results may lead to small and fast spin-based on-chip logic devices.
Evidence that appropriately engineered quantum states outperform both standard and N00N states in the precision of phase estimation — even in the presence of losses and decoherence — is presented. The results show that the strategy for realizing the quantum enhancement of metrology is quite distinct from protecting quantum information encoded in light.
By exploiting the Keldysh scaling — universal wavelength scaling laws in strong-field physics — direct temporal characterization of high-harmonics is demonstrated using sum-frequency-generation cross-correlation frequency-resolved optical gating (SFG XFROG).
A noiseless linear amplifier for quantum states of an optical field is demonstrated. The amplifier is also used to enhance entanglement through a technique known as distillation. Such amplification and distillation may be useful for quantum cloning, metrology and communications.
A graphene-based photodetector with unprecedented photoresponsivity and the ability to perform error-free detection of 10 Gbit s−1s data streams is demonstrated. The results suggest that graphene-based photonic devices have a bright future in telecommunications and other optical applications.
