Events

Please see below for a list of forthcoming (and archived past) events.

All Upcoming Events

14
JUN'17
Title: Dr Noel Healy Seminar
Seminar (Durham University)
This event will take place at 12:00-13:00 in PH8 Abstract TBC
Speakers: Dr. Noel Healy
31
MAY'17
Title: Vortices, turbulence and rogue waves in lasers and fluids of light
Seminar (Durham University)
This event will take place at 12:00-13:00 in PH8 Rogue waves are characterized by rare peak intensities that are much higher than the long-time average height of the oscillations in a medium. These waves occur unexpectedly and are typically accompanied by wide and/or deep troughs before and after the event. In nonlinear optical cavities, experimental evidence of deterministic rogue waves was first provided in lasers with injected signals. The dynamics of these systems, however, are confined to one spatial dimension. In this talk we describe a mechanism for the generation of fully two-dimensional spatio-temporal rogue waves in the presence of turbulence of interacting optical vortices. We consider the dynamics in the transverse plane of the complex Ginzburg-Landau (CGL) and complex Swift-Hohenberg equations in the presence of an external forcing. These equations are equivalent to the hydrodynamics of a viscous, compressible and irrotational fluid. Without spatio-temporal coupling, chaos, turbulence and, consequently, rogue waves are forbidden. With spatio-temporal coupling and below the locking threshold, we demonstrate phase and amplitude instabilities leading to regimes of defect-mediated turbulence with interacting optical vortices. Depending on the density of the moving vortices, short distance interactions lead to sudden, rare, large and randomly positioned peaks of the light intensity. The small aspect ratio, the full 2D character and the quick dynamics represent major advantages of transverse optical devices for studying the generation and control of rare events with applications, by universality, in hydrodynamics and oceanography. The CGL model equations have a broad range of applications in optics, ranging from broad area lasers to optical parametric oscillators, and to polaritons in semiconductor microcavities.