A low-impedance radio-frequency circuit for fast spin manipulations in cold alkali atoms
Year: 2025
Authors: Scazza F., Del Pace G., Pieri L., Concas R., Kwon WJ., Roati G.
Autors Affiliation: CNR, Ist Nazl Ott INO, I-50019 Sesto Fiorentino, Italy; European Lab Nonlinear Spect LENS, I-50019 Sesto Fiorentino, Italy; Univ Trieste, Dipartimento Fis, I-34127 Trieste, Italy; Univ Firenze, Dipartimento Fis & Astron, I-50019 Sesto Fiorentino, Italy; Radioteknos, I-50142 Florence, Italy; Ist Italiano Ric Metrol INRiM, I-10135 Turin, Italy; Ulsan Natl Inst Sci & Technol UNIST, Dept Phys, Ulsan 44919, South Korea.
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 similar to 4 to about 7.5 A for 100 W of RF driving. This allows us to obtain a RF coupling field of about 0.035 G / root W at the atomic sample location. The system is robust and versatile, as it generates a large RF field without compromising 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 similar or equal to 18.5 kHz, that is, a pi-pulse duration of about 27 mu s, between two of the lowest states of Li-6 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.
Journal/Review: REVIEW OF SCIENTIFIC INSTRUMENTS
Volume: 96 (10) Pages from: 104713-1 to: 104713-10
More Information: We thank Andreas Trenkwalder, Michael Jag, Alessio Ciamei, Matteo Zaccanti, and Marco De Pas for useful discussions; Caterina Credi for help with 3D printing; and the LENS Quantum Gases group for constant support. This work was supported by the Italian Ministry of University and Research under the PRIN2017 project CEnTraL and the PNRR MUR Project No. PE0000023-NQSTI. The authors acknowledge support from the European Union – NextGenerationEU for the Integrated Infrastructure Initiative in Photonics and Quantum Sciences – I-PHOQS (Grant Nos. IR0000016, ID D2B8D520, and CUP B53C22001750006). This publication has also received funding under the Horizon Europe program HORIZON-CL4-2022-QUANTUM-02-SGA via Project No. 101113690 (PASQuanS2.1).KeyWords: Fermi; PolaronsDOI: 10.1063/5.0276530
