Rydberg states are used in our one atom Maser experiment because they offer a large dipole moment and couple strongly to low numbers of microwave photons in a high-Q cavity. Here, we report the absolute frequencies of the P 3/2 states for principal quantum numbers n = 36-63. These measurements were made with a three step laser excitation scheme. A wavemeter was calibrated against a frequency comb to provide accurate absolute frequency measurements over the entire range, reducing the measurement uncertainty to 1 MHz. We compare the spectroscopic results with known frequency measurements as a test of measurement accuracy.

Precision measurements of quantum defects in the Rydberg states of Rb B Sanguinetti, H O Majeed, M L Jones et al. -Frequency metrology in the near-infrared spectrum of H217O and H218O molecules: testing a new inversion method for retrieval of energy levels A Gambetta, E Fasci, A Castrillo et al. Abstract. A three-step laser excitation scheme is used to make absolute frequency measurements of highly excited nF 7/2 Rydberg states in 85 Rb for principal quantum numbers n = 33-100. This work demonstrates the first absolute frequency measurements of rubidium Rydberg levels using a purely optical detection scheme. The Rydberg states are excited in a heated Rb vapour cell and Doppler-free signals are detected via purely optical means. All of the frequency measurements are made using a wavemeter that is calibrated against a Global Positioning System (GPS)-disciplined self-referenced optical frequency comb. We find that the measured levels have a very high frequency stability, and are especially robust against electric fields. The apparatus has allowed measurements of the states to an accuracy of 8.0 MHz. The new measurements are analysed by extracting the modified Rydberg-Ritz series parameters.

State selective field ionization detection techniques in physics require a specific progression through a complicated atomic state space to optimize state selectivity and overall efficiency. For large principle quantum number n, the theoretical models become computationally intractable and any results are often rendered irrelevant by small deviations from ideal experimental conditions, for example external electromagnetic fields. Several different proposals for quantum information processing rely heavily upon the quality of these detectors. In this paper, we show a proof of principle that it is possible to optimize experimental field profiles in situ by running a genetic algorithm to control aspects of the experiment itself. A simple experiment produced novel results that are consistent with analyses of existing results.

We demonstrate a three step laser stabilization scheme for excitation to nP and nF Rydberg states in 85 Rb, with all three lasers stabilized using active feedback to independent Rb vapor cells. The setup allows stabilization to the Rydberg states 36P 3/2 -70P 3/2 and 33F 7/2 -90F 7/2 , with the only limiting factor being the available third step laser power. We study the scheme by monitoring the three laser frequencies simultaneously against a self-referenced optical frequency comb. The third step laser, locked to the Rydberg transition, displays an Allan deviation of 30 kHz over 1 second and <80 kHz over 1 hour. The scheme is very robust and affordable, and it would be ideal for carrying out a range of quantum information experiments.

Abstract. We present an experimental setup of optimized acousto-optic modulator designed for observing a V-type electromagnetically induced transparency resonance in the D 1 line of rubidium-87, with the full width at half maximum being equal to 2.7 MHz. Possible artefacts and undesirable influences on the signal resulting from this method are discussed in detail. The solutions to such technical challenges as beam steering and intensity fluctuations are found in optimization of optical setup. The reported method offers a number of advantages such a single external-cavity diode laser to create a bichromatic optical field outside the laser, whereby both the coupling and probe beams have identical properties. Moreover, the both beams are equally affected by environmental perturbations to the laser. Subsequently, the influence of mode hopping, beam-power fluctuation and frequency drift on the resonance can be eliminated. This negates a need in complicated and expensive temperature and current stabilizations, as well as in a locking unit. The simplicity and stability of the improved setup make our method suitable for many applications based upon electromagnetically induced transparency, especially those in the field of precision measurements.