Instantaneous processing of "slow light": amplitude-duration control, storage, and splitting

Storage of up-converted telecom photons in a doped crystal

We report on an experiment that demonstrates the frequency up-conversion of telecommunication wavelength single-photon-level pulses to be resonant with a $\mathrm{Pr}^{3+}$:$\mathrm{Y}_2\mathrm{Si}\mathrm{O}_5$ crystal. We convert the telecom photons at $1570\,\mathrm{nm}$ to $606\,\mathrm{nm}$ using a periodically-poled potassium titanyl phosphate nonlinear waveguide. The maximum device efficiency (which includes all optical loss) is inferred to be $η_{\mathrm{dev}}^{\mathrm{max}} = 22 \pm 1\,%$ (internal efficiency $η_{\mathrm{int}} = 75\pm8\,%$) with a signal to noise ratio exceeding 1 for …

高效的、可逆的光到自旋转换用于固态量子记忆

Efficient and reversible optical-to-spin conversion for solid-state quantum memories

本研究通过优化实现了高效的光到自旋转换，实现了固态量子记忆中单光子态的长时长存储。

Storing images in warm atomic vapor

Reversible and coherent storage of light in atomic medium is a key-stone of future quantum information applications. In this work, arbitrary two-dimensional images are slowed and stored in warm atomic vapor for up to 30 $μ$s, utilizing electromagnetically induced transparency. Both the intensity and the phase patterns of the optical field are maintained. The main limitation on the storage resolution and duration is found to be the diffusion of atoms. A techniqueanalogous to phase-shift lithography is employed to diminish the effect of diffusion on the visibility of the reconstructed image.

Coherent spin control at the quantum level in an ensemble-based optical memory

Long-lived quantum memories are essential components of a long-standing goal of remote distribution of entanglement in quantum networks. These can be realized by storing the quantum states of light as single-spin excitations in atomic ensembles. However, spin states are often subjected to different dephasing processes that limit the storage time, which in principle could be overcome using spin-echo techniques. Theoretical studies have suggested this to be challenging due to unavoidable spontaneous emission noise in ensemble-based quantum memories. Here we demonstrate spin-echo manipulation of …

Efficient Coherent Control by Optimized Sequences of Pulses of Finite Duration

Reliable long-time storage of arbitrary quantum states is a key element for quantum information processing. In order to dynamically decouple a spin or quantum bit from a dephasing environment, we introduce an optimized sequence of $N$ control pulses of finite durations $τ\pp$ and finite amplitudes. The properties of this sequence of length $T$ stem from a mathematically rigorous derivation. Corrections occur only in order $T^{N+1}$ and $τ\pp^3$ without mixed terms such as $T^Nτ\pp$ or $T^Nτ\pp^2$. Based on existing experiments, a concrete setup for the verification of the properties of the adv…

Polarization insensitive frequency conversion for an atom-photon entanglement distribution via a telecom network

Quantum network with a current telecom photonic infrastructure is deficient in quantum storages that keep arbitrary quantum state in sufficient time duration for a long-distance quantum communication with quantum repeater algorithms. Atomic quantum storages have achieved subsecond storage time corresponding to 1000 km transmission time for a telecom photon through a quantum repeater algorithm. However, the telecom photon is not directly accessible to typical atomic storages. Solid state quantum frequency conversions fill this wavelength gap and add more abilities, for example, a frequency mult…

相互作用多能级量子系统的强驱动 Floquet 工程：从有限时长控制到涌现对称性

Strong-Drive Floquet Engineering of Interacting Qudits: From Finite-Duration Controls to Emergent Symmetry

本研究提出强驱动 Floquet 理论，将实验可实现的有限时长脉冲波形纳入相互作用多能级量子系统的有效相互作用设计，可产生新相互作用与对称性，为该类系统的控制设计提供可扩展分析框架。

脉冲持续时间敏感的高阶谐波及从手性拓扑威耳半导体产生的阿秒局部手性光

Pulse-duration-sensitive high harmonics and attosecond locally-chiral light from a chiral topological Weyl semimetal

研究揭示了手性拓扑威耳半导体RhSi中脉冲持续时间对高阶谐波产生及阿秒局部手性光生成的关键作用。