Propagation of spatially partially coherent emission from a vertical-cavity surface-emitting laser.
Recently we observed a strong reduction of spatial coherence of the emission of large-aperture vertical-cavity surface-emitting lasers when they are driven by microsecond electrical pulses [Opt. Express 13, 9337 (2005)]. We study the influence of this partial spatial coherence on the propagation characteristics. The spatial decoherence manifests itself in the formation of a Gaussian far-field intensity distribution. We measure the transverse pulse profile from near to far field and see that the shape-invariant far-field regime starts after 140 microm in the pulsed regime as opposed to several centimeters in continuous wave operation. This value matches quantitatively calculations made with a novel partially coherent propagation model without any free fitting parameters.
Peeters
Michael
M
Department of Applied Physics and Photonics, Vrije Universiteit Brussel, Belgium. michael.peeters@ieee.org
Verschaffelt
Guy
G
Speybrouck
Johan
J
Thienpont
Hugo
H
Danckaert
Jan
J
Turunen
Jari
J
Vahimaa
Pasi
P