Cavity-dumped nanosecond Cr:LiSAF laser in the 985–1030 nm region for versatile seeding of Yb-based amplifiers

We report nanosecond (ns) cavity-dumped operation of a low-cost diode-pumped Cr:LiSAF laser around 1000 nm. The system is pumped with one 1-W single-emitter multimode diode at 665 nm. A Pockell cell (PC) and thin-film-polarizer (TFP) combination placed inside the cavity chops up an adjustable portion of the intracavity power and creates a variable time-dependent output coupler. Via adjusting the length and magnitude of the electrical signal going into the PC, output pulses with pulsewidths in the 2.5–500 ns range and with peak power levels above 10 W are generated at repetition rates up to 100 kHz. The central wavelength of the pulses could be smoothly tuned in the 985–1030 nm region, and is only limited by the anti-reflection coating bandwidth of the current PC and TFP. This versatile nanosecond source with 100 nJ level energies could serve as an attractive low-cost seed source for Yb-based amplifiers, including the cryogenic Yb:YLF systems.

Regime of small number of photons in the cavity for a singleemitter laser

The model of a single-emitter laser generating in the regime of small number of photons in the cavity mode is theoretically investigated. Based on a system of equations for different moments of the field operators the analytical expressions for mean photon number and photon number variance are obtained. Using the master equation approach the differential equation for the phase-averaged quasi-probability Q is derived. For some limiting cases the exact solutions of this equation are found.

Dressed emitters as impurities

Dressed states forming when quantum emitters or atoms couple to a photonic bath underpin a number of phenomena and applications, in particular nonradiating effective interactions occurring within photonic bandgaps. Here, we present a compact formulation of the resolvent-based theory for calculating atom-photon dressed states built on the idea that the atom behaves as an effective impurity. This establishes an explicit connection with the standard impurity problem in condensed matter. Moreover, it allows us to formulate and settle – independently of the bath Hamiltonian – a number of properties previously known only for specific models or not entirely formalized. The framework is next extended to the case of more than one emitter, which is used to derive a general expression of dissipationless effective Hamiltonians explicitly featuring the overlap of single-emitter dressed bound states.

“Amplified Spontaneous Emission” in Micro- and Nanolasers

Amplified Spontaneous Emission is ubiquitous in systems with optical gain and is responsible for many opportunities and shortcomings. Its role in the progression from the simplest form of thermal radiation (single emitter spontaneous emission) all the way to coherent radiation from inverted systems is still an open question. We critically review observations of photon bursts in micro- and nanolasers, in the perspective of currently used measurement techniques, in relation to threshold-related questions for small devices. Corresponding stochastic predictions are analyzed, and contrasted with burst absence in differential models, in light of general phase space properties. A brief discussion on perspectives is offered in the conclusions.