Trap loss spectroscopy of ultra-cold Rydberg atoms involved in microwave fields.

Trap loss spectroscopy, based on fluorescence detection, provides a real-time measurement technique that is advantageous for ultra-cold atomic systems, to monitor the interaction between microwave fields and Rydberg atoms. By employing the polarization combinations of excitation lasers and microwave fields, we achieve trap loss spectroscopy of multi-path transitions in magnetic Rydberg hyperfine states and observe Zeeman broadening. The contributions of laser power, Zeeman effect, and collision effects to the broadening of the trap loss spectrum were comprehensively analyzed. Additionally, we have observed the broadening and splitting of the trap loss spectrum in response to variations in microwave field power and frequency. The transition from broadening to splitting of the spectral profile is observed with an increase in microwave field power. The full width at half maximum (FWHM) of trap loss spectroscopy exhibited a proportional relationship with the square root of microwave power, while the peak separation demonstrated a direct proportionality with higher microwave power. Our detailed exploration of trap loss spectroscopy under microwave fields may provide what we believe to be a novel approach for microwave field sensing.