Temporal Localized Turing Patterns in Vertical External-Cavity Surface-Emitting Laser

Abstract

Localized structures (LS) in lasers have been actively sought for all-optical information processing. So far, two distinct approaches have been developed for achieving LS: one leading to addressable stationary peaks of light in the transverse section of the resonator, the other leading to addressable mode-locked pulses having a fundamental mode spatial profile. Here we show that temporal localized patterns appear in nearly self-imaging Vertical External-Cavity Surface-Emitting Lasers (VECSELs) with an intracavity saturable absorber. The observed patterns consist of a combination of an axial plane-wave with a set of tilted waves having a hexagonal arrangement in the Fourier space. In the time domain these patterns are individually addressable mode-locked pulses having a duration of about ten picoseconds. The theoretical analysis shows that the emergence of these pulsating patterns is a signature of a Turing instability whose critical wave vector depends on spherical aberrations of the optical elements. Our result shows that large aspect-ratio VECSELs offer unique opportunities for studying spatio-temporal phenomena and it paves the way to the generation of spatio-temporal LS.

Spatiotemporally reconfigurable light in degenerate laser cavities

“…The interference of the two beams generates a stripe pattern in the near-field profile at each spot. Tilted beams emission is typical of degenerate cavities [40][41][42] and it is related to spherical aberrations of the optical elements of the cavity, which become more and more relevant close to SI conditions. Moreover, the interference pattern in the near-field enable an effective saturation of the SESAM.…”