Efficient Three-Dimensional Sub-Doppler Cooling of ${}^{40}$Ca${}^{+}$ in a Penning Trap

Abstract

We demonstrate efficient sub-Doppler laser cooling of the three eigenmodes of a ${}^{40}$Ca${}^{+}$ ion confined in a compact Penning trap operating with a magnetic field of 0.91 T. Using the same set of laser beams as required for the initial Doppler laser cooling operation, we detune the laser frequencies to produce a narrow two-photon dark resonance. The process achieves a 1/e cooling time constant of 108(8) $\mu$s, ultimately reducing the mean thermal axial mode occupation from 72(23) to 1.5(3) in 800 $\mu$s as measured by resonantly probing an electric quadrupole transition near 729 nm. A parametric drive is applied to the trap electrodes which coherently exchanges the axial mode occupation with that of each radial mode, allowing for three-dimensional sub-Doppler cooling using only the axially-propagating laser beams. This sub-Doppler cooling is achieved for an axial oscillation frequency of ${\omega }_z=2\pi \times$221 kHz, which places the motion well outside of the Lamb Dicke confinement regime at the Doppler laser cooling limit. Our measured cooling rate and final mode occupation are in good agreement with a semiclassical model which combines a Lindblad master equation solution for ion-photon interactions with classical harmonic oscillator motion of the trapped ion.

arXiv comment8 pages, 6 figures

References in corpus (24)

• High-fidelity quantum logic gates using trapped-ion hyperfine qubits
• High-fidelity two-qubit quantum logic gates using trapped calcium-43 ions
• High-Fidelity Universal Gate Set for ${}^9$Be${}^{+}$ Ion Qubits
• Experimental demonstration of ground state laser cooling with electromagnetically induced transparency
• High-Fidelity Bell-State Preparation with ${}^{40}$Ca${}^{+}$ Optical Qubits
• EIT ground-state cooling of long ion strings
• Cooling atomic motion with quantum interference
• Near ground-state cooling of two-dimensional trapped-ion crystals with more than 100 ions
• Efficient ground-state cooling of large trapped-ion chains with an EIT tripod scheme
• Resolved-sideband laser cooling in a Penning trap
• A high fidelity light-shift gate for clock-state qubits
• Experimental and theoretical investigation of a multi-mode cooling scheme using multiple EIT resonances
• Penning micro-trap for quantum computing
• Two mode coupling in a single ion oscillator via parametric resonance
• Multi-zone trapped-ion qubit control in an integrated photonics QCCD device
• Sideband cooling of the radial modes of motion of a single ion in a Penning trap
• Broadening of the drumhead mode spectrum due to in-plane thermal fluctuations of two-dimensional trapped ion crystals in a Penning trap
• Dynamics of axialized laser-cooled ions in a Penning trap
• Laser cooling in the Penning trap: an analytical model for cooling rates in the presence of an axializing field
• Electromagnetically-Induced-Transparency Cooling of High-Nuclear-Spin Ions
• Dark-resonance Doppler cooling and high fluorescence in trapped Ca-43 ions at intermediate magnetic field
• Laser cooling of high temperature oscillator by multi-level system
• Individual-Ion Addressing and Readout in a Penning Trap
• In-situ-tunable spin-spin interactions in a Penning trap with in-bore optomechanics