We demonstrate a three step laser stabilisation scheme for excitation to nP and nF Rydberg states in 85Rb, with all three lasers stabilised using active feedback to independent Rb vapour cells. The setup allows stabilisation to the Rydberg states 36P
3/2 to 70P3/2 and 33F7/2 to 90F7/2, 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.
In this paper we present the full theoretical model of a modified Ives-Stillwell experiment where counter propagating lasers are used to form a narrow interference fringe when the lasers form a double resnonance. This narrow resoannce can be as small
as 1 Hz wide and therefore provides a connection between the atomic resonance in its rest frame and the laser frequency in the lab frame. The current paper builds on a simplified approach suggested recently and presents a fully developed theory of the interaction within the Lorentz vilating electrodynamics of the Standard Model Extension.
High efficiency single photon detection is an interesting problem for many areas of physics, including low temperature measurement, quantum information science and particle physics. For optical photons, there are many examples of devices capable of d
etecting single photons with high efficiency. However reliable single photon detection of microwaves is very difficult, principally due to their low energy. In this paper we present the theory of a cascade amplifier operating in the microwave regime that has an optimal quantum efficiency of 93%. The device uses a microwave photon to trigger the stimulated emission of a sequence of atoms where the energy transition is readily detectable. A detailed description of the detectors operation and some discussion of the potential limitations of the detector are presented.
