Multiplicity of Solutions for Nonlocal Elliptic System of p, q -Kirchhoff Type

This paper is concerned with the following nonlocal elliptic system of p,q -Kirchhoff type Under bounded condition on M and some novel and periodic condition on F, some new results of the existence of two solutions and three solutions of the above mentioned nonlocal elliptic system are obtained by means of Bonanno's multiple critical points theorems without the PalaisSmale condition and Ricceri's three critical points theorem, respectively

Femtosecond laser-induced quantum-beat superfluorescence of atomic oxygen in a flame

Among different approaches to generate mirrorless lasing, resonant multiphoton pumping of gas constituents by deep-UV laser pulses exhibits so far the highest efficiency and produces measurable lasing energies, but the underlying mechanism was not yet fully settled. Here, we report lasing generation from atomic oxygen in a methane-air flame via femtosecond two-photon excitation. Temporal profiles of the lasing pulses were measured for varying concentrations of atomic oxygen, which shows that the peak intensity and time delay of the lasing pulse approximately scales as N and 1/N, respectively, where N represents the concentration. These scaling laws match well with the prediction of oscillatory superfluorescence (SF), indicating that the lasing we observed is essentially SF rather than amplified spontaneous emission. In addition, the quantum-beating effect was also observed in the time-resolved lasing pulse. A theoretical simulation based on nonadiabatic Maxwell-Bloch equations well reproduces the experimental observations of the temporal dynamics of the lasing pulses. These results on fundamentals should be beneficial for the better design and applications of lasing-based techniques