Continuous-wave all-optical single-photon transistor based on a Rydberg-atom ensemble

Abstract

Continuous-wave (cw) architectures provide a promising route to interface disparate quantum systems by relaxing the need for precise synchronization. While essential cw components, including microwave single-photon transistors and microwave-optical converters, have been explored, an all-optical cw single-photon transistor has remained a missing piece. We propose a high-efficiency, high-gain implementation using Rydberg atoms, in which a control photon disrupts the transmission of a continuous probe beam via the van der Waals interaction. This device completes the set of components required for cw processing of quantum signals and paves the way for all-optical processing at the quantum level.

Figures (3)

• Figure 1: (a) System sketch depicting the cavity version of the Rydberg-based SPT. (b) Atomic level scheme illustrating probe and control $\Xi$ systems with distinct couplings and detunings, including the inter-$\Xi$ system van der Waals interaction $\mathcal{V}_{kl}$. (c) Free space device configuration, with probe and control fields propagating within the Rydberg cloud spanning the interval $\{0,L\}$.
• Figure 2: Cavity-model results, with a 3D atomic ensemble of $N=10^3$ randomly placed atoms (isotropic Gaussian distribution); $\kappa_\mathrm{p}=\kappa_\mathrm{c}=\gamma_{e_\mathrm{p}}=\gamma_{e_\mathrm{c}}, \Omega_\mathrm{p}/\gamma_{e_\mathrm{c}}=10, \Delta/\gamma_{e_\mathrm{c}} = 180,\Omega_\mathrm{c}/\gamma_{e_\mathrm{c}} = 5$ for $C_\mathrm{c}=10,20,50,100$, and $\Delta/\gamma_{e_\mathrm{c}} = 4C_\mathrm{c}/5, \Omega_\mathrm{c}/\gamma_{e_\mathrm{c}} =20,45,$ for $C_\mathrm{c}=1000,5000$. (a) IM probability as a function of probe strength for $\mathrm{Re}[\overline{C}_\mathrm{b,p}]\approx0.5$ and varying $C_\mathrm{c}$, with optimized $\delta$. (b) SPT efficiency as a function of average blockaded cooperativity, with optimized $\delta, |\alpha_{\mathrm{in,p}}|^2$. (c) SPT efficiency (solid) and gain (dashed) as functions of cooperativity, with optimized $\delta, |\alpha_{\mathrm{in,p}}|^2,\overline{C}_\mathrm{b,p}$. For panels (b) and (c) fitted polynomials serve as guides to the eye, whereas points represent simulation data.
• Figure 3: FS-model results, with a 1D atomic ensemble of $N = 10^3$ randomly placed atoms (Gaussian distribution): $\Delta/\gamma_{e_\mathrm{c}}=4 d_\mathrm{c},\Omega_\mathrm{c} = \Delta/40, \Omega_\mathrm{p}/\gamma_{e_\mathrm{c}}=10$, $d_\mathrm{1p}=d_\mathrm{1c}=\gamma_{e_\mathrm{p}}/\gamma_{e_\mathrm{c}}=1$. (a) IM probability as a function of probe strength for $\mathrm{Re}[\overline{d}_\mathrm{b,p}]\approx2$ and varying $d_\mathrm{c}$, with optimized $\delta$. (b) SPT efficiency as a function of average blockaded optical depth, with optimized $\delta, |\alpha_{\mathrm{in,p}}|^2$. (c) SPT efficiency (solid) and gain (dashed) as functions of optical depth, with optimized $\delta, |\alpha_{\mathrm{in,p}}|^2,\overline{d}_\mathrm{b,p}$. For panels (b) and (c) fitted polynomials serve as guides to the eye, whereas points represent simulation data.