相关论文: Quantum erasing of laser emission in N$_2^+$
Generation of laser-like narrow bandwidth emissions from nitrogen molecular ions generated in intense near- and mid-infrared femtosecond laser fields has aroused much interest because of the mysterious physics underlying such a phenomenon…
Electron-positron pair creation in a standing wave is explored using a parameter-free quantum kinetic equation. Field strengths and frequencies corresponding to modern optical lasers induce a material polarisation of the QED vacuum, which…
An intense femtosecond laser pulse can generate ultraviolet air lasing, offering a promising remote light source. A long-standing hypothesis is whether it is seeded by a self-generated spectral component, such as the second harmonic that is…
While conventional lasers are based on gain media with three or four real levels, unconventional lasers including virtual levels and two-photon processes offer new opportunities. We study lasing that involves a two-photon process through a…
We propose a broadband, femtosecond two-photon excitation scheme for efficient population transfer to the ultra-narrow linewidth $1s2s\ ^1S_0$ metastable state in helium. Using $120$ nm vacuum ultraviolet (VUV) femtosecond laser pulses, we…
We predict collective 'free-space' lasing in a dense nanoscopic emitter arrangement where dipole-dipole coupled atomic emitters synchronize their emission and exhibit lasing behavior without the need for an optical resonator. At the example…
Harnessing structured light is fascinating for its multi-disciplinary applications, e.g., in remote driving microrobots, sensing, communications, and ultrahigh resolution imaging. Here we experimentally demonstrated the generation of a…
We report the physical reasons of a curious decrease in the crater depth observed for long delays in experiments with femtosecond double pulses. Detailed hydrodynamic modeling demonstrates that the ablation mechanism is dumped when the…
The first continuous-wave two-photon absorption laser-induced stimulated emission (CTALISE) is demonstrated. The 7^1S-6^1P transition in mercury at 1014nm wavelength is used and selective lasing of different isotopes is observed.
A non-dispersing wave packet has been attracting much interest from various scientific and technological viewpoints. However, most quantum systems are accompanied by anharmonicity, so that retardation of quantum wave-packet dispersion is…
Recently, S. Mitryukovskiy et al. presented experimental evidence showing that backward stimulated radiation at 337 nm can be obtained from plasma filaments in nitrogen gas pumped by circularly polarized 800 nm femtosecond pulses (Opt.…
The laser-like coherent emission at 391nm from N$_2$ gas irradiated by strong 800nm pump laser and weak 400nm seed laser is theoretically investigated. Recent experimental observations are well simulated, including temporal profile, optical…
The effect of ultrashort laser-induced morphological changes upon irradiation of silicon with double pulse sequences is investigated under conditions that lead to mass removal. The temporal delay between twelve double and equal-energy…
We report an ultrafast and efficient way to create the maximum coherence between the two lower states in a -like atomic systems, driven by two nonlinearly chirped few-cycle pulses. The phenomenon of coherent population trapping and…
The methods producing cold molecules from cold atoms tend to leave molecular ensembles with substantial residual internal energy. For instance, Cs2 molecules initially formed via photoassociation of cold Cs atoms are in several vibrational…
We show lasing without population inversion in a closed four-level atomic system which is no longer incoherently pumped on the transition at which lasing occurs. The four-level system can overcome some limits in the typical lambda-type and…
Structured light has attracted great interest in scientific and technical fields. Here, we demonstrate the first generation of structured air lasing in N2+ driven by 800 nm femtosecond laser pulses. By focusing a vortex pump beam at 800 nm…
A two-dimensional model atom is employed to study the ionization behavior of initially excited atomic states in highly-frequent intense laser pulses beyond the dipole approximation. An additional regime of ionization suppression is found at…
An extreme ultraviolet (EUV) single attosecond pulse passing through a laser-dressed dense gas is studied theoretically. The weak EUV pulse pumps the helium gas from the ground state to the 2s2p(1P) autoionizing state, which is coupled to…
A source of ultrashort pulses of light in the 2 {\mu}m region was constructed using supercontinuum broadening from an erbium mode-locked laser. The output spectrum spanned 1000 nm to 2200 nm with an average power of 250 mW. A pulse width of…