A planar cloverleaf antenna for the creation of circularly polarized microwave fields

W Yuan, S Zhang, N Bigagli, C Warner… - arXiv preprint arXiv …, 2023 - arxiv.org
arXiv preprint arXiv:2306.14791, 2023arxiv.org
We report on the design and characterization of a compact microwave antenna for atomic
and molecular physics experiments. The antenna is comprised of four loop antennas
arranged in cloverleaf shape, allowing for precise adjustment of polarization by tuning the
relative phase of the loops. We optimize the antenna for left-circularly polarized microwaves
at 3.5 GHz and characterize its performance using ultracold NaCs molecules as a precise
quantum sensor. Observing an unusually high Rabi frequency of $2\pi\times 46$ MHz, we …
We report on the design and characterization of a compact microwave antenna for atomic and molecular physics experiments. The antenna is comprised of four loop antennas arranged in cloverleaf shape, allowing for precise adjustment of polarization by tuning the relative phase of the loops. We optimize the antenna for left-circularly polarized microwaves at 3.5 GHz and characterize its performance using ultracold NaCs molecules as a precise quantum sensor. Observing an unusually high Rabi frequency of MHz, we extract an electric field amplitude of 33(2) V/cm at 22 mm distance from the antenna. The polarization ellipticity is 2.3(4) degrees, corresponding to a 24 dB suppression of right-circular polarization. The cloverleaf antenna is planar and provides large optical access, making it highly suitable for quantum control of atoms and molecules, and potentially other quantum systems that operate in the microwave regime.
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