An efficient high-current circuit for fast radio-frequency spectroscopy in cold atomic gases

Abstract

We design and implement a low-impedance, high-current radio-frequency (RF) circuit, enabling fast coherent coupling between magnetic levels in cold alkali atomic samples. It is based on a compact shape-optimized coil that maximizes the RF field coupling with the atomic magnetic dipole, and on coaxial transmission-line transformers that step up the field-generating current flowing in the coil by a factor $\sim 4$ to about $7.5$A for $100$W of RF driving. This allows to obtain a RF coupling field of about $0.035\text{G}/\sqrt{\text{W}}$ at the atomic sample location. The system is robust and versatile, as it generates a large RF field without compromising on the available optical access, and its central resonant frequency can be adjusted in situ. Our approach provides a cost-effective, reliable solution, featuring a negligible level of interference with surrounding electronic equipment thanks to its symmetric layout. We test the circuit performance using a maximum RF power of $80$W at a frequency around $82$MHz, which corresponds to a measured Rabi frequency ${\Omega }_R/2\pi \simeq 18.5$kHz, i.e. a $\pi$-pulse duration of about $27\mu$s, between two of the lowest states of ${}^6$Li at an offset magnetic field of $770$G. Our solution can be readily adapted to other atomic species and vacuum chamber designs, in view of an increasing modularity of cold atom experiments.

8 pages, 6 figures

References in corpus (26)

• Observation of the Pairing Gap in a Strongly Interacting Fermi Gas
• Observation of Fermi Polarons in a Tunable Fermi Liquid of Ultracold Atoms
• Using photoemission spectroscopy to probe a strongly interacting Fermi gas
• Metastability and Coherence of Repulsive Polarons in a Strongly Interacting Fermi Mixture
• Observation of Attractive and Repulsive Polarons in a Bose-Einstein Condensate
• Attractive and repulsive Fermi polarons in two dimensions
• Bose polarons in the strongly interacting regime
• Ultrafast many-body interferometry of impurities coupled to a Fermi sea
• Repulsive Fermi polarons in a resonant mixture of ultracold ${}^6$Li atoms
• Bose polarons near quantum criticality
• Radio-frequency dressed state potentials for neutral atoms
• Universal many-body response of heavy impurities coupled to a Fermi sea
• Non-equilibrium quantum dynamics and formation of the Bose polaron
• Measurement of the Homogeneous Contact of a Unitary Fermi gas
• Universal gate operations on nuclear spin qubits in an optical tweezer array of ${}^{171}$Yb atoms
• Near-Unitary Spin Squeezing in ${}^{171}$Yb
• Two and Three-body Contacts in the Unitary Bose Gas
• Transverse Demagnetization Dynamics of a Unitary Fermi Gas
• Spectral response and contact of the unitary Fermi gas
• A Universal Trimer in a Three-Component Fermi Gas
• Quasiparticle lifetime of the repulsive Fermi polaron
• Time-resolved observation of competing attractive and repulsive short-range correlations in strongly interacting Fermi gases
• Physics of ultracold Fermi gases revealed by spectroscopies
• The strongly driven Fermi polaron
• A radiofrequency voltage-controlled current source for quantum spin manipulation
• A Radio-Frequency Emitter Design for the Low-Frequency Regime in Atomic Experiments

Cited by in corpus (1)

• Programmable Assembly of Ground State Fermionic Tweezer Arrays