Polarization preserving ultra fast optical shutter for quantum information processing

利用光学克尔快门超快测量能量-时间纠缠

Ultrafast Measurement of Energy-Time Entanglement with an Optical Kerr Shutter

本文利用单模光纤中的光学克尔快门实现亚皮秒级能量-时间纠缠光子对关联测量，并结合联合光谱测量通过违反时间-带宽不等式验证纠缠。

Time-bin to Polarization Conversion of Ultrafast Photonic Qubits

The encoding of quantum information in photonic time-bin qubits is apt for long distance quantum communication schemes. In practice, due to technical constraints such as detector response time, or the speed with which co-polarized time-bins can be switched, other encodings, e.g. polarization, are often preferred for operations like state detection. Here, we present the conversion of qubits between polarization and time-bin encodings using a method that is based on an ultrafast optical Kerr shutter and attain efficiencies of 97% and an average fidelity of 0.827+/-0.003 with shutter speeds near …

Ultrafast single-photon detection based on optical Kerr gates at GHz rates

The ultrafast detection of single photons is currently restricted by the limited time resolution (a few picoseconds) of the available single-photon detectors. Optical gates offer a faster time resolution, but so far they have been mostly applied to ensembles of emitters. Here, we demonstrate through a semi-analytical model that the ultrafast time-resolved detection of single quantum emitters can be possible using an optical-Kerr-shutter (OKS) at GHz rates under focused illumination. This technique provides sub-picosecond time resolution, while keeping a gate efficiency at around 85 \%. These f…

On the ultraviolet finiteness of parity-preserving $U(1) \times U(1)$ massive QED$_3$

The parity-preserving $U_A(1)\times U_a(1)$ massive QED$_3$ is ultraviolet finiteness -- exhibits vanishing $β$-functions, associated to the gauge coupling constants (electric and pseudochiral charges) and the Chern-Simons mass parameter, and all the anomalous dimensions of the fields -- as well as is parity and gauge anomaly free at all orders in perturbation theory. The proof is independent of any regularization scheme and it is based on the quantum action principle in combination with general theorems of perturbative quantum field theory by adopting the Becchi-Rouet-Stora (BRS) algebraic re…

Ultrafast time-division demultiplexing of polarization-entangled photons

Maximizing the information transmission rate through quantum channels is essential for practical implementation of quantum communication. Time-division multiplexing is an approach for which the ultimate rate requires the ability to manipulate and detect single photons on ultrafast timescales while preserving their quantum correlations. Here we demonstrate the demultiplexing of a train of pulsed single photons using time-to-frequency conversion while preserving their polarization entanglement with a partner photon. Our technique converts a pulse train with 2.69 ps spacing to a frequency comb wi…

Demonstration of Ultra Low Dissipation Optomechanical Resonators on a Chip

Cavity-enhanced radiation-pressure coupling of optical and mechanical degrees of freedom gives rise to a range of optomechanical phenomena, in particular providing a route to the quantum regime of mesoscopic mechanical oscillators. A prime challenge in cavity optomechanics has however been to realize systems which simultaneously maximize optical finesse and mechanical quality. Here we demonstrate for the first time independent control over both mechanical and optical degree of freedom within one and the same on-chip resonator. The first direct observation of mechanical normal mode coupling in …