title: Propagation of spatially partially coherent emission from a vertical-cavity surface-emitting laser.
abstract: 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.
authors.affiliation: Department of Applied Physics and Photonics, Vrije Universiteit Brussel, Belgium. michael.peeters@ieee.org
authors.forename: Michael
authors.initials: M
authors.lastname: Peeters
authors.forename: Guy
authors.initials: G
authors.lastname: Verschaffelt
authors.forename: Johan
authors.initials: J
authors.lastname: Speybrouck
authors.forename: Hugo
authors.initials: H
authors.lastname: Thienpont
authors.forename: Jan
authors.initials: J
authors.lastname: Danckaert
authors.forename: Jari
authors.initials: J
authors.lastname: Turunen
authors.forename: Pasi
authors.initials: P
authors.lastname: Vahimaa