Quantum-Assisted Electrometry using Electromagnetically Induced Transparency with Rydberg Atoms in a Vapor Cell

We demonstrate a new type of atomic standard for microwave electric fields using Rydberg atoms in a vapor cell. We have used a bright resonance prepared within an electromagnetically induced transparency window in a Rydberg atom to achieve an electrometer with a sensitivity of 30 $\mu$V cm$^{-1}$ $\sqrt{Hz}$$^{-1}$. In addition, we have demonstrated vector electrometry at a resolution of 0.5$^{o}$ with similar sensitivity. Recently, we have also shown this scheme can achieve sub-wavelength spatial resolution $\lambda$/1933. Our experimental results agree very well with the finite difference time domain calculations. We present a summary of our experiments on atom-based electrometry to date.