Generation Of Coherent Photons Research Articles

Attosecond electron-beam technology: a review of recent progress.

Electron microscopy and diffraction with ultrashort pulsed electron beams are capable of imaging transient phenomena with the combined ultrafast temporal and atomic-scale spatial resolutions. The emerging field of optical electron beam control allowed the manipulation of relativistic and sub-relativistic electron beams at the level of optical cycles. Specifically, it enabled the generation of electron beams in the form of attosecond pulse trains and individual attosecond pulses. In this review, we describe the basics of the attosecond electron beam control and overview the recent experimental progress. High-energy electron pulses of attosecond sub-optical cycle duration open up novel opportunities for space-time-resolved imaging of ultrafast chemical and physical processes, coherent photon generation, free electron quantum optics, electron-atom scattering with shaped wave packets and laser-driven particle acceleration. Graphical Abstract.

Fundamental Limits to Coherent Photon Generation with Solid-State Atomlike Transitions.

Coherent generation of indistinguishable single photons is crucial for many quantum communication and processing protocols. Solid-state realizations of two-level atomic transitions or three-level spin-Λ systems offer significant advantages over their atomic counterparts for this purpose, albeit decoherence can arise due to environmental couplings. One popular approach to mitigate dephasing is to operate in the weak-excitation limit, where the excited-state population is minimal and coherently scattered photons dominate over incoherent emission. Here we probe the coherence of photons produced using two-level and spin-Λ solid-state systems. We observe that the coupling of the atomiclike transitions to the vibronic transitions of the crystal lattice is independent of the driving strength, even for detuned excitation using the spin-Λ configuration. We apply a polaron master equation to capture the non-Markovian dynamics of the vibrational manifolds. These results provide insight into the fundamental limitations to photon coherence from solid-state quantum emitters.

Resonance fluorescence of ladder- and triangular-type three-level systems: Continuous coherent photon generation

We develop a new quantum molecular dynamics (QMD) type nuclear transport code to simulate heavy-ion collisions for RAON, a new accelerator complex under construction in Korea. At RAON, the rare isotope beams with energies from a few MeV/n to a few hundreds MeV/n will be utilized. QMD is one of the widely used theoretical methods and is useful for both theoretical and experimental purposes. We describe our QMD model with the numerical realization. The validity of the code is tested by comparing our simulation results with experimental data and also results from other transport codes in 197Au+197Au collisions at Elab = 90 - 120 MeV/n. Finally, we present a brief discussion on applicability and outlook of our code.

Direct photonic coupling of a semiconductor quantum dot and a trapped ion.

Coupling individual quantum systems lies at the heart of building scalable quantum networks. Here, we report the first direct photonic coupling between a semiconductor quantum dot and a trapped ion and we demonstrate that single photons generated by a quantum dot controllably change the internal state of a Yb^{+} ion. We ameliorate the effect of the 60-fold mismatch of the radiative linewidths with coherent photon generation and a high-finesse fiber-based optical cavity enhancing the coupling between the single photon and the ion. The transfer of information presented here via the classical correlations between the σ_{z} projection of the quantum-dot spin and the internal state of the ion provides a promising step towards quantum-state transfer in a hybrid photonic network.

Photon-phonon lasing in indirect gap semiconductors

The use of photon-phonon interband electron transitions in indirect gap semiconductors to obtain stimulated phonon generation is suggested. To increase the phonon emission rate the photon part of the two-quantum transition including the emission of photons and phonons can be stimulated by external radiation. At a high enough intensity of the stimulating radiation the phonon gain turns out to be equal to the phonon losses in a particular acoustic mode. In this case one can expect the stimulated generation of coherent photons, i.e. phonon lasing. The required energy flux density of stimulating radiation is determined. Dynamics of the photon-phonon generation in indirect gap semiconductors is investigated with aid of the rate equations. Conditions are found for which simultaneous lasing of photons and phonons can be sustained without external radiation to drive the process. Numerical estimations are made for indirect gap semiconductors of Ge and Si.