A planar cloverleaf antenna for circularly polarized microwave fields in atomic and molecular physics experiments

Area of Science:

• Atomic, Molecular, and Optical (AMO) Physics
• Quantum Control
• Microwave Engineering

Background:

• Precise control of microwave fields is crucial for atomic and molecular physics experiments.
• Existing antenna designs may lack the necessary polarization control or optical access for advanced quantum applications.

Purpose of the Study:

• To design and characterize a compact microwave antenna for atomic and molecular physics.
• To achieve precise control over microwave polarization, specifically left-circular polarization (LCP).
• To evaluate the antenna's performance using ultracold molecules as quantum sensors.

Main Methods:

• A novel cloverleaf antenna design with four loop antennas was developed.
• The antenna was optimized for left-circularly polarized microwaves at 3.5 GHz.
• Near-field performance was characterized using ultracold Sodium-Cesium (NaCs) molecules as a quantum sensor.

Main Results:

• An unusually high Rabi frequency of 2π × 46.1(2) MHz was observed.
• An electric field amplitude of 33(2) V/cm was extracted at 22 mm distance.
• Polarization ellipticity was measured at 2.3(4)°, with 24 dB suppression of right-circular polarization.

Conclusions:

• The planar cloverleaf antenna offers precise polarization control and large optical access.
• This antenna is highly suitable for quantum control of atoms and molecules.
• The design has potential applications for other quantum systems operating in the microwave regime.