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Proceedings Paper

Spatial coherence of random laser emission
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Paper Abstract

Lasing action in disordered media has been studied extensively in recent years and many of its properties are well understood. However, few studies have considered the spatial coherence in these systems, despite initial observations indicating that random lasers exhibit much lower spatial coherence than conventional lasers. We performed a systematic, experimental investigation of the spatial coherence of random laser emission as a function of the scattering mean free path and the excitation volume. Lasing was achieved under optical excitation and spatial coherence was characterized by imaging the emission spot onto a Young's double slit and collecting the interference fringes in the far field. We observed dramatic differences in the spatial coherence within our parameter space. Specifically, we found that samples with a shorter mean free path relative to the excitation volume exhibited reduced spatial coherence. We provide a qualitative explanation of our experimental observations in terms of the number of excited modes and their spatial orientation. This work provides a means to realize intense, spatially incoherent laser emission for applications in which speckle or spatial cross talk limits performance.

Paper Details

Date Published: 12 September 2011
PDF: 7 pages
Proc. SPIE 8095, Active Photonic Materials IV, 80950P (12 September 2011); doi: 10.1117/12.893091
Show Author Affiliations
B. Redding, Yale Univ. (United States)
M. A. Choma, Yale School of Medicine (United States)
H. Cao, Yale Univ. (United States)

Published in SPIE Proceedings Vol. 8095:
Active Photonic Materials IV
Ganapathi S. Subramania; Stavroula Foteinopoulou, Editor(s)

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