Theory of a coherently pumped maser in various cavity limits

Yoh‐Han Pao

N. S. Ginzburg, E. R. Kocharovskaya, A. S. Sergeyev

Superradiant operating mode in masers and lasers with distributed feedback is found. Namely, on the basis of two-level model of active medium in low-Q cavity, it is shown that chaotic series of utmost short powerful pulses of coherent radiation may be generated under CW pumping. The ways of achievement and properties of superradiant regime in various quantum microwave and optical oscillators are analyzed using numeric simulations.

Christoph W. Zollitsch, Jonathan Breeze

We present a quantum theory of diamond masers operating at any temperature using a cavity quantum electrodynamical framework. Special attention is paid to the recently demonstrated room-temperature solid-state masers based on nitrogen-vacancy (NV) defect centers in diamond, but the model can easily be modified for other photoexcited chromophores such as pentacene-doped paraterphenyl, vacancies in silicon-carbide or boron nitride. We show that the eight energy levels involved in the optically pumped NV center polarization process can be mapped to a simple pumped two-level-system. We then derive simple analytical expressions for the optical pump threshold condition for masing as well as the steady-state microwave output power which can be used to design and predict maser performance. Finally, we investigate second-order correlations and find that typical diamond masers operate in an intermediate regime between the good and bad cavity limits where photon emission is driven by both stimulated and superradiant processes.

Gerhard Rempe, Marlan O. Scully, HERBERT WALTHER

We review our recent work on the nonclassical radiation field of a one-atom maser. The maser cavity is cooled to 0.5 K to exclude thermal photons and has a quality factor of 3 × 10 10 . Velocity-selected Rydberg atoms pump the maser. The field inside the cavity is measured via the fluctuations in the number of atoms leaving the cavity in the lower maser level which are up to 40% below the Poisson level. This corresponds to photon-number fluctuations 70% below the vacuum-state limit. The one-atom maser is the only maser system which leads to nonclassical radiation even when pumping processes with Poissonian statistics are used. We analyse and propose new experiments based on the one-atom maser leading to new studies of the quantum measurement process.

Y.-H. Pao