Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

International Photonics and Optoelectronics Meetings

Theoretical Investigation on Dispersive effect from one-dimensional random media Pumped by Femtosecond-Lasing Pulses

Hai Liu, Xiaocong Niu, Shengyu Jing, Zihui Ren

Published Jan 1, 2012• 0 citations
Publisher

Abstract

The pulsing random lasing from the Rh6G solution with TiO2 scattering particles is investigated by solving Maxwell’s equations and rate equations of electronic population simultaneously. The pumping rate is described by a time function with duration of tens or hundreds of femtoseconds. A one-dimensional (1D) dispersive model is proposed to explain the experiment results. The results indicate that although the dispersion in optical domain is relatively small, the random lasing depends strongly on the pumping process pumped by femtosecond-lasing pulses.

DOI
10.1364/ltst.2012.sth4a.25

Related papers

The Method of Semi-classical Theory for Resonance Characteristic of Random Laser in Random Media

Xiangyin Li

A model of random laser with semi-classical theory is presented.It couples Maxwell's equations with density matrix of excited atom in a disordered system.So Maxwell-Bloch equations for random laser are obtained.A finite-difference time-domain method is used to solve Maxwell-Bloch equations directly.We studied the pattern of field and localized modes of random laser.A critical pumping rate W~c_p exists for the appearance of the lasing peaks in random system.The number of lasing modes increases with the pumping rate and it is saturated finally.

Jiangxi kexue•Jan 1, 2005•0 citations

Linear dispersive effect on random lasing modes

Yong Liu, Jinsong Liu, Kejia Wang

A model, by combining Maxwell's equations with all-parameters of Sellmeier's fitting equations and four-level rate equations, is built to investigate linear dispersive effect on the property of random lasing modes. Computed results show that the first excited modes for both dispersive and non-dispersive scattering cases have almost the same resonant frequency but the spectral intensity for dispersive case is lower than that for non-dispersive case, and there exist more modes in the whole spectra for dispersive case. Further analysis demonstrates that threshold of random lasing in dispersive case is higher than that of the non-dispersive case.

Optics Express•Jun 27, 2011•1 citation

Influence of Spatial Localization on Lasing Threshold of Quasi-State Mode in One-Dimension Random Media

Jinsong Liu

Based on the time dependent theory of random lasers, which was built via combining Maxwell equations with the rate equations of a four-level atomic system, the output intensity of a lasing mode varying with the pumping rate is simulated for a two-dimensional random active medium by use of the finite difference time domain method. Results show that the pumping rate dependence of the output intensity presents not only a threshold property, but also a saturation property, just like that of lasing modes in conventional lasers. Charactering the mode's localization extent via the mode's area indicates that the stronger the mode's localization extent is, the lower the mode's threshold is. However, such a relation is not a one-to-one correspondence, meaning that the mode's localization extent is an important fact to determine the mode's threshold, but is not alone.

Optics & Optoelectronic Technology•Jan 1, 2006•0 citations

Threshold and saturation properties of two-dimensional random lasers and mode selection

Jinsong Liu, Liu Hai, Chun Wang +4 more

Based on the time dependent theory of random lasers, which was established via combining Maxwell equations with the rate equations of a four-level atomic system, the output intensity of lasing modes varying with the pump rate and area as well as the medium's size and shape is simulated for two-dimensional random media by use of the finite difference time domain method. Results show that the pump-rate dependence of the output intensity presents not only a threshold property, but also a saturation property, just like that of the lasing modes in conventional lasers. Based on the dependence of mode property on the medium's and pump's parameters, the mode-selection approaches are proposed for two-dimensional random lasers, which are quite different from those performed in conventional lasers.

Acta Physica Sinica•Jan 1, 2006•4 citations

Lasing in a random amplifying medium: Spatiotemporal characteristics and nonadiabatic atomic dynamics

Lucia Florescu, Sajeev John

We study the dynamics of lasing from photonic paints excited by short, localized, optical pulses, using a time-dependent diffusion model for light propagating in the medium containing active atoms. The full time-dependent, nonadiabatic nonlinear response of the atomic system to the local optical field intensity is described using the Einstein rate equations for absorption and emission of light. Solving the time-dependent diffusion equation for the light intensity in the medium with nonlinear gain and loss, we derive detailed information on the spectral, spatial, and temporal properties of the emitted laser light. Our model recaptures the effects of scatterers to narrow the emission spectral linewidth and to narrow the emitted pulse duration, at a specific threshold pump intensity. Our model also describes how this threshold pump intensity decreases with scatterer density and excitation spot diameter, in excellent agreement with experimental results.

Physical Review E•Sep 20, 2004•21 citations

Numerical study of amplified spontaneous emission and lasing in random media

Jonathan Andreasen, Hui W. Cao

We simulate the transition from amplified spontaneous emission (ASE) to lasing in random systems with varying degrees of mode overlap. This is accomplished by solving the stochastic Maxwell-Bloch equations with the finite-difference time-domain method. Below lasing threshold, the continuous emission spectra are narrowed by frequency-dependent amplification. Our simulations reproduce the stochastic emission spikes in the spectra. Well-defined peaks, corresponding to the system resonances, emerge at higher pumping and are narrowed by stimulated emission before lasing takes place. Noise tends to distribute pump energy over many modes, resulting in multimode operation. Well above the lasing threshold, the effects of noise lessen and results become similar to those without noise. By comparing systems of different scattering strength, we find that weaker scattering extends the transition region from ASE to lasing, where the effects of noise are most significant.

arXiv:1008.3993•Physical Review A•Dec 29, 2010•32 citations
The pulsing random lasing from the Rh6G solution with TiO2 scattering particles is investigated by solving Maxwell’s equations and rate equations of electronic population simultaneously. The pumping rate is described by a time function with duration of tens or hundreds of femtoseconds. A one-dimensional (1D) dispersive model is proposed to explain the experiment results. The results indicate that although the dispersion in optical domain is relatively small, the random lasing depends strongly on the pumping process pumped by femtosecond-lasing pulses.
A model of random laser with semi-classical theory is presented.It couples Maxwell's equations with density matrix of excited atom in a disordered system.So Maxwell-Bloch equations for random laser are obtained.A finite-difference time-domain method is used to solve Maxwell-Bloch equations directly.We studied the pattern of field and localized modes of random laser.A critical pumping rate W~c_p exists for the appearance of the lasing peaks in random system.The number of lasing modes increases with the pumping rate and it is saturated finally.
A model, by combining Maxwell's equations with all-parameters of Sellmeier's fitting equations and four-level rate equations, is built to investigate linear dispersive effect on the property of random lasing modes. Computed results show that the first excited modes for both dispersive and non-dispersive scattering cases have almost the same resonant frequency but the spectral intensity for dispersive case is lower than that for non-dispersive case, and there exist more modes in the whole spectra for dispersive case. Further analysis demonstrates that threshold of random lasing in dispersive case is higher than that of the non-dispersive case.
Based on the time dependent theory of random lasers, which was built via combining Maxwell equations with the rate equations of a four-level atomic system, the output intensity of a lasing mode varying with the pumping rate is simulated for a two-dimensional random active medium by use of the finite difference time domain method. Results show that the pumping rate dependence of the output intensity presents not only a threshold property, but also a saturation property, just like that of lasing modes in conventional lasers. Charactering the mode's localization extent via the mode's area indicates that the stronger the mode's localization extent is, the lower the mode's threshold is. However, such a relation is not a one-to-one correspondence, meaning that the mode's localization extent is an important fact to determine the mode's threshold, but is not alone.
Based on the time dependent theory of random lasers, which was established via combining Maxwell equations with the rate equations of a four-level atomic system, the output intensity of lasing modes varying with the pump rate and area as well as the medium's size and shape is simulated for two-dimensional random media by use of the finite difference time domain method. Results show that the pump-rate dependence of the output intensity presents not only a threshold property, but also a saturation property, just like that of the lasing modes in conventional lasers. Based on the dependence of mode property on the medium's and pump's parameters, the mode-selection approaches are proposed for two-dimensional random lasers, which are quite different from those performed in conventional lasers.
We study the dynamics of lasing from photonic paints excited by short, localized, optical pulses, using a time-dependent diffusion model for light propagating in the medium containing active atoms. The full time-dependent, nonadiabatic nonlinear response of the atomic system to the local optical field intensity is described using the Einstein rate equations for absorption and emission of light. Solving the time-dependent diffusion equation for the light intensity in the medium with nonlinear gain and loss, we derive detailed information on the spectral, spatial, and temporal properties of the emitted laser light. Our model recaptures the effects of scatterers to narrow the emission spectral linewidth and to narrow the emitted pulse duration, at a specific threshold pump intensity. Our model also describes how this threshold pump intensity decreases with scatterer density and excitation spot diameter, in excellent agreement with experimental results.
We simulate the transition from amplified spontaneous emission (ASE) to lasing in random systems with varying degrees of mode overlap. This is accomplished by solving the stochastic Maxwell-Bloch equations with the finite-difference time-domain method. Below lasing threshold, the continuous emission spectra are narrowed by frequency-dependent amplification. Our simulations reproduce the stochastic emission spikes in the spectra. Well-defined peaks, corresponding to the system resonances, emerge at higher pumping and are narrowed by stimulated emission before lasing takes place. Noise tends to distribute pump energy over many modes, resulting in multimode operation. Well above the lasing threshold, the effects of noise lessen and results become similar to those without noise. By comparing systems of different scattering strength, we find that weaker scattering extends the transition region from ASE to lasing, where the effects of noise are most significant.