Reduced filamentation in high power semiconductor lasers

Peter M. W. Skovgaard, John McInerney, Peter O'Brien

Research output: Chapter in Book/Report/Conference proceedingArticle in proceedingsResearch

Abstract

High brightness semiconductor lasers have applications in fields ranging from material processing to medicine. The main difficulty associated with high brightness is that high optical power densities cause damage to the laser facet and thus require large apertures. This, in turn, results in spatio-temporal instabilities such as filamentation which degrades spatial coherence and brightness. We first evaluate performance of existing designs with a “top-hat” shaped transverse current density profile. The unstable nature of highly excited semiconductor material results in a run-away process where small modulations in the optical field causes spatial hole-burning and thus filamentation. To reduce filamentation we propose a new, relatively simple design based on inhomogeneous pumping in which the injected current has a gradual transverse profile. We confirm the improved laser performance theoretically and experimentally. Experimentally, we generate transverse current profiles by using standard lithography to define a digitated contact pad. Experimental results confirm that the current density is significantly altered and show completely filamentation-free operation up to 34 times threshold.
Original languageEnglish
Title of host publicationProc., Annual meeting of the Danish Optical Society
Number of pages14
Place of PublicationLyngby
PublisherDOPS
Publication date1999
Publication statusPublished - 1999
Event1999 Annual meeting of the Danish Optical Society - Lyngby, Denmark
Duration: 18 Nov 199919 Nov 1999

Conference

Conference1999 Annual meeting of the Danish Optical Society
CountryDenmark
CityLyngby
Period18/11/199919/11/1999

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