Millimeter wave detection via Autler-Townes splitting in rubidium Rydberg atoms

In this paper, we demonstrate the detection of millimeter waves via Autler-Townes splitting in Rb-85 Rydberg atoms. This method may provide an independent, atom-based, SI-traceable method for measuring mm-wave electric fields, which addresses a gap in current calibration techniques in the mm-wave regime. The electric-field amplitude within a rubidium vapor cell in the WR-10 wave guide band is measured for frequencies of 93.71 GHz and 104.77 GHz. Relevant aspects of Autler-Townes splitting originating from a four-level electromagnetically induced transparency scheme are discussed. We measured the E-field generated by an open-ended waveguide using this technique. Experimental results are compared to a full-wave finite element simulation. (C) 2014 AIP Publishing LLC.