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n-type Ge/SiGe terahertz quantum cascade laser are investigated using non-equilibrium Green's functions calculations. We compare the temperature dependence of the terahertz gain properties with an equivalent GaAs/AlGaAs QCL design. In the…

Mesoscale and Nanoscale Physics · Physics 2019-05-01 T. Grange , D. Stark , G. Scalari , J. Faist , L. Persichetti , L. Di Gaspare , M. De Seta , M. Ortolani , D. J. Paul , G. Capellini , S. Birner , M. Virgilio

The advent of high-intensity ultrafast laser pulses has opened new opportunities for controlling and designing quantum materials. In particular, terahertz (THz) pulses can resonantly drive optical phonon modes, enabling dynamic manipulation…

Quantum Physics · Physics 2025-12-22 Yulong Qiao , Richard. Matthias Geilhufe

We develop a theory of optomechanical cooling with a squeezed input light field. We show that Stokes heating transitions can be \emph{fully} suppressed when the driving field is squeezed below the vacuum noise level at an appropriately…

Quantum Physics · Physics 2016-11-30 Muhammad Asjad , Stefano Zippilli , David Vitali

We report on a new design of terahertz quantum cascade laser based on a single, potential-inserted quantum well active region. The quantum well properties are engineered through single monolayer InAs inserts. The modeling is based on…

Materials Science · Physics 2017-04-05 R. Benchamekh , J. -M. Jancu , P. Voisin

In this paper, we study the laser cooling mechanisms with a new quantum theory approach by applying a new Schrodinger equation, which can describe a particle in conservative and non-conservative force field. With the new theory, we prove…

Direct laser slab face-cooling by a fluid crossing the main and pump laser beams is an important method to reach high average laser powers. However, the flow regime is usually maintained at low Reynolds numbers, to prevent the onset of…

Colloids with patchy metal coating under laser irradiation could act as local sources of heat due to the absorption of light. While for asymmetric colloids this could induce self-propulsion, it also leads to the generation of a slowly…

Soft Condensed Matter · Physics 2015-05-30 Ramin Golestanian

The ion heating mechanism in the context of laser interacting with plasma immersed in a strong magnetic field is studied. The magnetic field is chosen to be strong for laser electromagnetic field propagation inside the plasma to be governed…

We propose an embedding of standard active particle models in terms of two-temperature processes. One temperature refers to an ambient thermal bath, and the other temperature effectively describes ``hot spots,'' i.e., systems with few…

Statistical Mechanics · Physics 2024-01-23 Faezeh Khodabandehlou , Christian Maes

Based on the phenomenological theory of heat diffusion, we show that the generated peak temperature $T_{\text{max}}$ after absorption of a laser pulse strongly depends on the pulse duration. We identify three different heat conduction…

Applied Physics · Physics 2020-02-26 Roman Shayduk , Peter Gaal

Quantum coherence has been demonstrated in various systems including organic solar cells and solid state devices. In this letter, we report the lower and upper bounds for the performance of quantum heat engines determined by the efficiency…

Quantum Physics · Physics 2018-04-18 Konstantin E. Dorfman , Dazhi Xu , Jianshu Cao

High power single mode quantum cascade lasers with a narrow far field are important for several applications including surgery or military countermeasure. Existing technologies suffer from drawbacks such as operation temperature and…

The established approach to laser cooling of solids relies on anti-Stokes fluorescence, for example from rare earth impurities in glass. Although successful, there is a minimum temperature to which such a process can cool set by the…

Quantum Physics · Physics 2025-01-24 Paul R. Eastham , Conor N. Murphy , Luisa Toledo Tude

We report a combined experimental and theoretical study of non-conventional lasing from higher multi-exciton states of a few quantum dot-photonic crystal nanocavity. We show that the photon output is fed from saturable quantum emitters…

Mesoscale and Nanoscale Physics · Physics 2016-03-04 S. Lichtmannecker , M. Florian , T. Reichert , M. Blauth , M. Bichler , F. Jahnke , J. J. Finley , C. Gies , M. Kaniber

We performed the experimental and theoretical study of the heating and damaging of ruthenium thin films induced by femtosecond laser irradiation. Results of an optical pump-probe thermoreflectance experiment with rotating sample allowing to…

Laser cooling of molecules employing broadband optical pumping involves a timescale separation between laser excitation and spontaneous emission. Here, we optimize the optical pumping step using shaped laser pulses. We derive two…

Quantum Physics · Physics 2013-12-24 Daniel M. Reich , Christiane P. Koch

The semiclassical theory of laser cooling is applied for the analysis of cooling of unbound atoms with the values of the ground and exited state angular moments 1/2 in a one-dimensional nondissipative optical lattice. We show that in the…

Optics · Physics 2011-10-05 N. A. Matveeva , A. V. Taichenachev , A. M. Tumaikin , V. I. Yudin

A novel method is presented for generating radiation using the beat wave associated with a bi-frequency laser pulse, to excite plasma oscillations in a plasma slab with a density gradient. By resonantly exciting a plasma wave, it can be…

Recent theoretical predictions hint at an implementation of a superradiant laser based on narrow optical clock transitions by using a filtered thermal beam at high density. Corresponding numerical studies give encouraging results but the…

Atomic Physics · Physics 2023-08-11 Martin Fasser , Christoph Hotter , David Plankensteiner , Helmut Ritsch

A near-minimal instance of optical cooling is experimentally presented wherein the internal-state entropy of a single atom is reduced more than twofold by illuminating it with broadband, incoherent light. Since the rate of optical pumping…

Quantum Physics · Physics 2024-11-08 Amanda Younes , Randall Putnam , Paul Hamilton , Wesley C. Campbell