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The violation of the no-signalling principle — information can be transmitted faster than light — is experimentally investigated using entangled photons. It can be simulated when the parity–time symmetrically evolved subspace is solely considered.
Cheap and sensitive gamma-ray detectors are desired for defence, medical and research applications. Solid-state gamma-radiation detectors made from solution-grown perovskites have now been demonstrated for multiple practical applications.
The local amplitude and phase of a single photon is retrieved using a method similar to classical holography. The interference of optical fields is replaced by the non-classical interference of spatially varying two-photon probability amplitudes.
Echo-enabled harmonic generation has been used to seed a free-electron laser and has been demonstrated up to the 75th harmonic, producing 32 nm light from a 2,400 nm laser.
Coherent transfer of an optical photon polarization state to a single nuclear spin in a nitrogen–vacancy defect centre in diamond is demonstrated without a high-finesse cavity. A storage time of 10 s is achieved with a transfer fidelity of 98%.
Direct f–2f self-referencing of a microresonator-based optical frequency comb is demonstrated at a repetition rate of 16.4 GHz. The carrier envelope offset frequency and repetition rate are stabilized to a hydrogen maser-based atomic clock.
Strong coupling between X-rays and matter excitations in arrays of alternating 57Fe and 56Fe layers is demonstrated. The results may open the door to X-ray quantum optics and strong coupling phenomena.
A silicon nitride ring resonator with implanted ytterbium ions offers a means for greatly enhanced ion–light interactions in an integrated optics platform.
By using a single-photon frequency converter based on quasi-phase-matched LiNbO3, frequency-domain Hong–Ou–Mandel interference is demonstrated between a heralded single photon at 780 nm and a weak laser pulse at 1,522 nm in a single spatial mode.
Photons are efficiently funnelled into a single molecule if they are nearly resonant with the sharp molecular transition. In this condition, the coherent nonlinear optical effect can be induced with only a few photons without high-finesse cavities.