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Proceedings Paper

Experiments and numerical simulations on lasing in random media
Author(s): Sushil Mujumdar; Renato Torre; Stefano Cavalieri; Diederik S. Wiersma
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Paper Abstract

We report numerical and experimental studies on multiple scattering media with gain. We describe Monte Carlo simulations that model the behavior of such a system through a three dimensional random walk of photons in a disordered medium with amplification. Two experimentally observed phenomena, viz. temperature tunable random lasing and ultra-narrow lasing modes, are analyzed using the model. We compare the results of our model with previous experimental results on a disordered dielectric of which the scattering strength could be tuned by changing the external temperature. The agreement between the numerical and experimental results enables us to predict the spectral features of the emission from the tunable random laser under various conditions. Results obtained from new experimental data are consistent with the predictions of the simulations. The model also explains the observation of ultra-narrow emission modes in random lasers without requiring optical cavities. The introduction of exponential gain in a multiple light scattering process strongly increases the importance of very long light paths. Such long paths are often neglected in passive disordered materials but we show that they can dominate the emission spectrum from an amplifying disordered system.

Paper Details

Date Published: 2 August 2004
PDF: 12 pages
Proc. SPIE 5508, Complex Mediums V: Light and Complexity, (2 August 2004); doi: 10.1117/12.561054
Show Author Affiliations
Sushil Mujumdar, European Lab. for Non-Linear Spectroscopy (Italy)
INFM (Italy)
Renato Torre, European Lab. for Non-Linear Spectroscopy (Italy)
INFM (Italy)
Stefano Cavalieri, European Lab. for Non-Linear Spectroscopy (Italy)
INFM (Italy)
Diederik S. Wiersma, European Lab. for Non-Linear Spectroscopy (Italy)
INFM (Italy)

Published in SPIE Proceedings Vol. 5508:
Complex Mediums V: Light and Complexity
Martin W. McCall; Graeme Dewar, Editor(s)

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