Evolution from modal to spatially incoherent emission of a broad-area VCSEL.
Broad-area vertical-cavity surface-emitting lasers (BA-VCSELs) can exhibit a state of spatially incoherent emission, as we recently reported in [M. Peeters et al., Opt. Express, 13, 9337 (2005)]. Here, we experimentally study the evolution of a BA-VCSEL under pulsed operation from well-defined modal emission with a multitude of transverse cavity modes to such spatially incoherent emission. The transition is studied using a high-speed intensified CCD camera and differential image analysis with which single-shot measurements of the imaged nearfield, farfield, spatial coherence, and spectral emission properties are acquired. This combination of experimental characterization tools allows for a detailed description of the BA-VCSEL's emission behavior, which is necessary for an in-depth understanding of the processes involved. We find the interplay between the thermal chirp and the build-up of a spatially distributed thermal lens to be decisive for the break-up of the global cavity modes.
Mandre
Shyam K
SK
Institute of Applied Physics, Darmstadt University of Technology, Schlossgartenstr. 7, D-64289 Darmstadt, Germany.
Elsässer
Wolfgang
W
Fischer
Ingo
I
Peeters
Michael
M
Verschaffelt
Guy
G
D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007834:Lasers; D008962:Models, Theoretical