An Optical Möbius Strip; On-Chip Photon Entanglement; New Quantum Interface; Longer-Distance Transmission; Bull's-Eye for Brighter Metamaterials; Flipping Signals from Photonic Crystals; Corning to Acquire Third Company; European Photonics Industry Sees an Uptick; 3-D Live Imaging; Self-Compressed IR Pulses on a Budget.
Abstract Quantum repeaters are required for realizing long-distance quantum communication. The quantum repeater consists of a quantum memory to store quantum information and an interface between photonic flying qubits and the memory qubits. Electron spins in gate-defined quantum dots (QDs), which have a relatively long coherence time and high electrical tunability, are promising candidates for such memory qubits because the fundamental technologies of detecting and manipulating single photoelectron spins have been established. The remaining challenge for the realization of quantum repeaters is an efficient coupling between photons and electron spins in the QDs. In this study, we discuss the enhancement of the transmission and the maintenance of the incident light polarization through bull’s eye structures on gate-defined QDs on the basis of electromagnetic field simulations.
The sidebands of stimulated Raman scattering initiated from vacuum fluctuations in hollow-core photonic crystal fiber filled with Raman gas exhibit surprisingly strong self- and mutual coherence [1] as well as persistence of coherence for much longer than the dephasing time T2[2]. This opens new prospects in a number of applications such as attosecond pulse generation and optical waveform synthesis. However, the spatiotemporal coherence dynamics underlying these results is not fully investigated and no rigorous theoretical simulation is available. This contribution discusses theoretical and experimental results that study this issue and explains the long-lived effect of the coherence on a delayed probe pulse in the pump-probe setup.