A compact gain-enhanced microwave helical antenna for ⁸⁷Rb atomic experiments

Area of Science:

• Atomic Physics
• Quantum Optics
• Microwave Engineering

Background:

• Coherent manipulation of ultracold atoms is crucial for quantum technologies.
• Precise control of atomic hyperfine transitions requires optimized microwave field generation.
• Existing antenna designs may limit the efficiency and fidelity of such manipulations.

Purpose of the Study:

• To design and characterize a compact, gain-enhanced microwave helical antenna.
• To improve the control of ultracold Rubidium-87 (Rb-87) atoms.
• To achieve higher Rabi frequencies for hyperfine level manipulation.

Main Methods:

• Modification of a standard helical antenna by replacing the reflecting plate with an enhancing cup.
• Characterization of antenna performance, including voltage standing wave ratio (VSWR) and gain, in the 6.73-6.93 GHz frequency range.
• Application of the enhanced antenna in experiments with ultracold Rb-87 atoms to measure Rabi frequencies.

Main Results:

• The enhanced helical antenna reduced the VSWR by 0.5 in the target frequency range.
• The antenna gain was increased by 1.25-1.63 dBi compared to a standard design.
• A Rabi frequency of 60(1) ×2π kHz was achieved for oscillations between Rb-87 ground-state hyperfine levels.

Conclusions:

• The gain-enhanced helical antenna provides improved microwave field control for ultracold atoms.
• This antenna design is effective for precise manipulation of Rb-87 hyperfine transitions.
• The enhanced antenna performance enables higher fidelity quantum operations in atomic experiments.