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Proceedings Paper

Spatio-temporal lasing dynamics in wave-chaotic and disordered cavities (Conference Presentation)
Author(s): Hui Cao

Paper Abstract

Broad-area semiconductor lasers are widely used in high-power applications including material processing, large-scale display and laser surgery as well as pump sources for solid-state and fiber lasers. A serious problem of such lasers are their instabilities which cause spatio-temporal and spectral fluctuations of output beams. Such instabilities are rooted in the nonlinear interactions of multiple lasing modes and the gain medium. Much effort has been invested in stabilizing the broad-area semiconductor lasers by minimizing the number of lasing modes, but with limited success. We propose and demonstrate a different approach for stabilization via complex interference in wave-chaotic or disordered cavities that maintains multi-mode operation. Instead of suppressing the filaments via external signals, we disrupt the coherent nonlinear processes that lead to their formation by using cavities with complex spatial structure to create many propagating waves with random phases. The complex interference of these waves prevents the formation of self-organized structures such as filaments that are prone to modulational instabilities. We demonstrate the generality and robustness of this approach through experiments and numerical simulations with two different systems, (i) two-dimensional (2D) microcavities featuring chaotic ray dynamics and (ii) one-dimensional (1D) cavities with random fluctuations of the refractive index. The chaotic ray dynamics and the structural disorder are responsible for the creation of multi-wave interference effects, respectively. Our approach can suppress spatiotemporal instabilities in broad-area semiconductor lasers without while keeping multimode operation. It is applicable to other types of lasers such as solid-state lasers and fiber lasers.

Paper Details

Date Published: 9 September 2019
Proc. SPIE 11082, Plasmonics: Design, Materials, Fabrication, Characterization, and Applications XVII, 1108207 (9 September 2019); doi: 10.1117/12.2525131
Show Author Affiliations
Hui Cao, Yale Univ. (United States)

Published in SPIE Proceedings Vol. 11082:
Plasmonics: Design, Materials, Fabrication, Characterization, and Applications XVII
Din Ping Tsai; Takuo Tanaka, Editor(s)

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