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Weakly scattering random lasers exhibit lasing modes that spatially overlap and can interact strongly via gain saturation. Consequently, lasing in high-threshold modes may be suppressed by strong low-threshold lasing modes. We numerically…

Optics · Physics 2012-02-22 Jonathan Andreasen , Hui Cao

Recent numerical and theoretical studies have demonstrated that the modes at threshold of a random laser are in direct correspondence with the resonances of the same system without gain, a feature which is well known in a conventional laser…

Optics · Physics 2011-11-24 Jonathan Andreasen , Patrick Sebbah , Christian Vanneste

The effects of the non-linearity of the medium on the growth rate of filamentation instability in a magnetized plasma interacting with an intense laser pulse, is investigated. The non-linearity of the medium, modeled by Kerr non-linearity,…

Plasma Physics · Physics 2018-02-22 Sepideh Dashtestani , Akbar Parvazian , Hamidreza Mohammadi

Semiclassical equations of lasing dynamics are re-derived for a lasing medium in a cavity with a spatially non-uniform dielectric constant. It is shown that the non-uniformity causes a radiative coupling between modes of the empty cavity.…

Disordered Systems and Neural Networks · Physics 2009-11-11 Lev Deych

A study on the effects of optical gain nonuniformly distributed in one-dimensional random systems is presented. It is demonstrated numerically that even without gain saturation and mode competition, the spatial nonuniformity of gain can…

Optics · Physics 2010-08-25 Jonathan Andreasen , Christian Vanneste , Li Ge , Hui Cao

In this article, we study the non-linear coupling between the stationary (i.e. the beating modulation signal) and transient (i.e. the laser quantum noise) dynamics of a laser subjected to frequency shifted optical feedback. We show how the…

A numerical study is presented of one-dimensional and two-dimensional random lasers as a function of the pumping rate above the threshold for lasing. Depending on the leakiness of the cavity modes, we observe that the stationary lasing…

Optics · Physics 2011-08-17 Jonathan Andreasen , Patrick Sebbah , Christian Vanneste

It is demonstrated, by means of analogue electronic simulation and theoretically, that external noise can markedly change the character of the response of a nonlinear system to a low-frequency periodic field. In general, noise of sufficient…

chao-dyn · Physics 2008-02-03 MI Dykman , DG Luchinsky , R Mannella , PVE McClintock , HE Short , ND Stein , N G Stocks

We propose a time-dependent partial differential equation model to investigate the dynamical behavior of the parity-time (PT) symmetric laser during the nonlinear stage of its operation. This model incorporates physical effects such as the…

Optics · Physics 2017-05-24 Jianke Yang

Random lasers are based on disordered materials with optical gain. These devices can exhibit either intensity or resonant feedback, relying on diffusive or interference behaviour of light, respectively, which leads to either coupling or…

We report on the creation of new lasing modes with spatially nonuniform distributions of optical gain in a one-dimensional random structure. It is demonstrated numerically that even without gain saturation and mode competition, the spatial…

Optics · Physics 2009-11-12 Jonathan Andreasen , Hui Cao

Controlling the flow of energy in a random medium is a research frontier with a wide range of applications. As recently demonstrated, the effect of disorder on the transmission of optical beams, may be partially compensated by wavefront…

Optics · Physics 2013-05-01 Marco Leonetti , Claudio Conti , Cefe Lopez

Nonlinear effects in emission and absorption spectra of gaseous systems are considered. It is shown that level splitting can be detected spectroscopically even if it is below the Doppler width. Conditions for distinguishing interference…

Quantum Physics · Physics 2007-05-23 T. Ya. Popova , A. K. Popov , S. G. Rautian , R. I. Sokolovskii

We analyze theoretically the effect of technical fluctuations on laser lineshape in terms of statistics of amplitude and phase noise and their respective bandwidths. While the phase noise tends to broaden the linewidth as the magnitude of…

We study laser generation in 1D distributed feedback lasers with amplifying and lossy layers. We show that when the lasing frequency differs from the transition frequencies of the amplifying medium, loss induced lasing may occur due to the…

The disorder induced feedback makes random lasers very susceptible to any changes in the scattering medium. The sensitivity of the lasing modes to perturbations in the disordered systems have been utilized to map the regions of…

Nonlinear dynamics can impact the performance of a particle accelerator in a number of different ways, depending on the type of the accelerator and the parameter regime in which it operates. Effects can range from minor changes in beam…

Accelerator Physics · Physics 2022-01-06 H. Bartosik , Y. Papaphilippou , A. Wolski

The mode dynamics of a random laser is investigated in experiment and theory. The laser consists of a ZnCdO/ZnO multiple quantum well with air-holes that provide the necessary feedback. Time-resolved measurements reveal multimode spectra…

Optics · Physics 2015-10-09 M. Höfner , H. -J. Wünsche , F. Henneberger

Nonlinear effects are omnipresent in thin films of ion conducting materials showing up as a significant increase of the conductivity. For a disordered hopping model general physical mechanisms are identified giving rise to the occurrence of…

Disordered Systems and Neural Networks · Physics 2015-06-18 Andreas Heuer , Lars Luehning

Propagation of light in a highly scattering medium is among the most fascinating optical effect that everyone experiences on an everyday basis and possesses a number of fundamental problems which have yet to be solved. Conventional wisdom…

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