Progress on deployable high-sensitive Rydberg-atom microwave receivers and its applications

We are developing Rydberg-atom microwave receivers with high sensitivity into portable devices for different types of applications. We designed a hybrid Rydberg-atom microwave receiver using a resonant waveguide cavity coupled with Rydberg atoms in a vapor cell. The hybrid receiver obtains enhancement in sensitivity of a factor of 14.2 in field of amplitude, as well as 650 MHz of frequency tunability working on ~10 GHz with an intrinsic Q-factor of 700. The noise equivalent field for the cavity receiver is NEF=1.58 µV/m/√Hz. Improved performance matched with a well-engineered cavity could significantly improve performance in sensitivity. At the same time, we demonstrated sub-wavelength angle-of-arrival detection using 3-color, all near-infrared excitation with Rydberg atoms. The angle-of-arrival is extracted by comparing phase difference between 2 detection channels with an error < 1^o. The all-near-infrared method allows the microwave receiver to employ portable rack-mounted lasers and electronics for deployable applications.