Improving Spectral Resolution of Rydberg Atom-Based Electrometry by 2 × 2 Laser Arrays

Rydberg atom-based electrometry based on electromagnetic induced transparency (EIT) and Autler–Townes splitting (EIT-AT) could achieve ultra-high sensitivity measurements. The amplitude and linewidth of EIT spectra significantly impact the accuracy of electric field measurements. This research utilizes cascade diffraction gratings to generate 2×2 probe laser arrays for the excitation of Rydberg atoms, thereby enhancing spectral resolution under the power broadening. Compared with one laser, the laser array boosts EIT amplitude, narrowing the linewidth from 23.53 MHz to 12.66 MHz, making EIT-AT more distinguishable under identical fields and achieving an enhancement of the sensitivity of 77.96 nV/cm/Hz. These results indicate that laser arrays can optimize the sensitivity of measurement systems based on the Rydberg EIT effect.