32 research outputs found
Microwave photo-association of fine-structure-induced Rydberg macro-dimer molecules of cesium
Long-range Rydberg macro-dimers are observed in an
ultracold cesium Rydberg gas for . Strong dipolar "flip"
(,
) and
"cross" () couplings lead to bound, fine-structure-mixed
macro-dimers at energies between the fine-structure levels. The
macro-dimers are measured by microwave photo-association from optically
prepared Rydberg pair states. Calculated adiabatic potential
curves are used to elucidate the underlying physics and to model the
macro-dimer spectra, with good overall agreement. Microwave photo-association
allows Franck-Condon tuning, which we have studied by varying the detuning of a
Rydberg-atom excitation laser. Further, in Stark spectroscopy we have measured
molecular DC electric polarizabilities that are considerably larger than those
of the atomic states. The large molecular polarizabilities may be caused by
high- mixing. The observed linewidths of the Stark-shifted molecular
lines provide initial evidence for intra-molecular induced-dipole-dipole
interaction
Measurement of the Near Field Distribution of a Microwave Horn Using a Resonant Atomic Probe
We measure the near field distribution of a microwave horn with a resonant atomic probe. The microwave field emitted by a standard microwave horn is investigated utilizing Rydberg electromagnetically inducted transparency (EIT), an all-optical Rydberg detection, in a room temperature caesium vapor cell. The ground 6S1/2 , excited 6P3/2 , and Rydberg 56D5/2 states constitute a three-level system, used as an atomic probe to detect microwave electric fields by analyzing microwave dressed Autler–Townes (AT) splitting. We present a measurement of the electric field distribution of the microwave horn operating at 3.99 GHz in the near field, coupling the transition 56D5/2→57P3/2 . The microwave dressed AT spectrum reveals information on both the strength and polarization of the field emitted from the microwave horn simultaneously. The measurements are compared with field measurements obtained using a dipole metal probe, and with simulations of the electromagnetic simulated software (EMSS). The atomic probe measurement is in better agreement with the simulations than the metal probe. The deviation from the simulation of measurements taken with the atomic probe is smaller than the metal probe, improving by 1.6 dB. The symmetry of the amplitude distribution of the measured field is studied by comparing the measurements taken on either side of the field maxima
Improvement of response bandwidth and sensitivity of Rydberg Receiver using multi-channel excitations
We investigate the response bandwidth of a superheterodyne Rydberg receiver
at a room-temperature vapor cell, and present an architecture of multi-channel
lasers excitation to increase the response bandwidth and keep sensitivity,
simultaneously. Two microwave fields, denoted as a local oscillator (LO)
and a signal field , couple two Rydberg states transition of
. In the presence of the LO field, the
frequency difference between two fields can be read out as an intermediate
frequency (IF) signal using Rydberg electromagnetically induced transparency
(EIT) spectroscopy. The bandwidth of the Rydberg receiver is obtained by
measuring the output power of IF signal versus the frequency difference between
two fields. The bandwidth dependence on the Rabi frequency of excitation lasers
is presented, which shows the bandwidth decrease with the probe Rabi frequency,
while it is quadratic dependence on the coupling Rabi frequency. Meanwhile, we
investigate the effect of probe laser waist on the bandwidth, showing that the
bandwidth is inversely proportional to the laser waist. We achieve a maximum
response bandwidth of the receiver about 6.8~MHz. Finally, we design an
architecture of multi-channel lasers excitation for increasing the response and
keeping the sensitivity, simultaneously. Our work has the potential to extend
the applications of Rydberg atoms in communications
Cesium + Rydberg molecules and their permanent electric dipole moments
Cs Rydberg-ground molecules consisting of a Rydberg, (33
39), and a ground state atom, 63 or 4, are
investigated by photo-association spectroscopy in a cold atomic gas. We observe
vibrational spectra that correspond to triplet and mixed
molecular states. We establish scaling laws for the energies of
the lowest vibrational states vs principal quantum number and obtain
zero-energy singlet and triplet -wave scattering lengths from experimental
data and a Fermi model. Line broadening in electric fields reveals the
permanent molecular electric-dipole moments; measured values agree well with
calculations. We discuss the negative polarity of the dipole moments, which
differs from previously reported cases.Comment: 5 pages, 4 figure