A photonic crystal receiver for Rydberg atom-based sensing
Hadi Amarloo, Mohammad Noaman, Su-Peng Yu, Donald Booth, Somayeh Mirzaee, Rajesh Pandiyan, Florian Christaller, James P. Shaffer
Rydberg atom-based sensors use atoms dressed by lasers to detect and measure radio frequency electromagnetic fields. The absorptive properties of the atomic gas, configured as a Rydberg atom-based sensor, change in the presence of a radio frequency electromagnetic field. While these sensors are reasonably sensitive, the best conventional radio frequency sensors still outperform Rydberg atom-based sensors with respect to sensitivity. One approach to increase the sensitivity of Rydberg atom-based sensors is to engineer the vapor cell that contains the atomic gas. In this work, we introduce a passive, all-dielectric amplifier integrated into a Rydberg atom-based sensor vapor cell. The vapor cell is a combination of a slot waveguide and a photonic crystal. The structural features of the vapor cell yield a power amplification of ~24 dB. The radio frequency electromagnetic field is coupled adiabatically into the slot waveguide and slowed to increase the interaction between the radio frequency field and the atoms to effectively amplify the incoming signal, i.e., increase the Rabi frequency on the radio frequency transition. The work shows the utility of vapor cell engineering for atom-based quantum technologies and paves the way for other such devices.
Fig. Photonic crystal vapor cell with slot region
filled with Cs atoms, and taper structure for mode
conversion of the incoming free space RF
electromagnetic wave. The holes are organized to
produce a photonic crystal that slows an RF elec-
tromagnetic wave propagating along the x axis
around a specific frequency. The slot is hermetically
sealed with glass on both sides and filled with Cs
atoms. The device uses a thermally activated getter
source to load the Cs atoms, shown as the disc in the
circular pocket separated from, but fluidly coupled
to the slot. Light is coupled in along the z axis after
being combined using beam splitters (BS) and
expanded using cylindrical lenses. The light is
detected using a photodiode (PD). A piece of glass
Parallel to the vapor cell is used to tune the frequency
of the resonance.