Sub-kilohertz excitation lasers for quantum information processing with Rydberg atoms

Abstract

Quantum information processing using atomic qubits requires narrow linewidth lasers with longterm stability for high fidelity coherent manipulation of Rydberg states. In this paper, we report on the construction and characterization of three continuous-wave (CW) narrow linewidth lasers stabilized simultaneously to an ultra-high finesse Fabry-Perot cavity made of ultra-low expansion (ULE) glass, with a tunable offset-lock frequency. One laser operates at 852 nm while the two locked lasers at 1018 nm are frequency doubled to 509 nm for excitation of 133 Cs atoms to Rydberg states. The optical beatnote at 509 nm is measured to be 260(5) Hz. We present measurements of the offset between the atomic and cavity resonant frequencies using electromagnetically induced transparency (EIT) for high-resolution spectroscopy on a cold atom cloud. The long-term stability is determined from repeated spectra over a period of 20 days yielding a linear frequency drift of ∼ 1 Hz/s. I. INTRODUCTIONThe field of quantum information processing (QIP) is an intensive research area. Its attractiveness lies in the possibility of speeding up classical problems and modelling complex quantum systems [1]. Neutral atoms present an attractive candidate for scalable QIP [2, 3] combining long coherence times of weakly interacting hyperfine ground states [4] with strongly interacting Rydberg states [5] to create pair-wise entanglement [6,7], perform deterministic quantum gates [8,9] and even realize a quantum simulator for Ising models [10].Rydberg excitation is typically performed using two-photon excitation due to weak single photon matrix elements from the ground state [11] and inconvenient UV wavelengths. Using a resonant two-photon excitation, Rydberg electromagnetically induced transparency (EIT) [12] can be exploited for laser frequency stabilization [13] as well as precision metrology of Rydberg state energies [14,15] and lifetimes [16], dc electric fields [17] and RF field sensors operating at both microwave [18,19] and THz [20] frequency ranges. For dense cold atom samples, the strong atomic interactions can be mapped onto the optical field to create non-linearities at the single photon level [21][22][23][24].For robust Rydberg excitation of atomic qubits for gate operations the two-photon excitation must be * Electronic address: jonathan.pritchard@strath.ac.uk

Entanglement of neutral-atom qubits with long ground-Rydberg coherence times

“…Rydberg excitation from |1 → |r = |69S 1/2 , m j = 1/2 uses light at 852 nm (Ω A ) and 509 nm (Ω C ) detuned by ∆ A /2π = 870 MHz from the |6S 1/2 , F = 4 → |6P 3/2 , F = 5 transition to reduce spontaneous emission. The Rydberg excitation lasers are stabilized to a high finesse ULE cavity to obtain sub-kHz linewidths (See [42] for further details).…”

Probing 10 μK stability and residual drifts in the cross-polarized dual-mode stabilization of single-crystal ultrahigh-Q optical resonators

“…High-precision clocks and oscillators are cornerstones for global navigation to provide accurate timing and distance information, via satellite-to-satellite or satellite-to-ground communications, for the synchronization of electronic device communications and for quantum information processing using atomic qubits 1–3 . Likewise, precision time–frequency transfer in timing links is helpful for synchronization and data exchange in coherent arrays, gravitation sensing, and relativity measurements 4 .…”

Realization of Deutsch–Jozsa Algorithm in Rydberg Atoms by Composite Nonadiabatic Holonomic Quantum Computation with Strong Robustness Against Systematic Errors

“…Combining with the limitation on Rabi frequency with the targeted twist, we find that 32.58 µW of 852‐nm laser () and 179.74 mW of 509‐nm laser () [ 108–110 ] is sufficient to observe the transition between ground states and excited state, in which, the laser intensity corresponding mW/cm −2 and mW/cm −2 , respectively. [ 106,111 ] From the above data analysis, it can be seen that our scheme is feasible in experiment.…”