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Full-Text Articles in Physics
Boundary Effects In Large-Aspect-Ratio Lasers, G.K. Harkness, W.J. Firth, John B. Geddes, J.V Moloney, E.M. Wright
Boundary Effects In Large-Aspect-Ratio Lasers, G.K. Harkness, W.J. Firth, John B. Geddes, J.V Moloney, E.M. Wright
John B. Geddes
We study theoretically the effect of transverse boundary conditions on the traveling waves foundin infinitely extended and positively detuned laser systems. We find that for large-aspect-ratiosystems, well above threshold and away from the boundaries, the traveling waves persist. Sourceand sink defects are observed on the boundaries, and in very-large-aspect-ratio systems these defectscan also exist away from the boundaries. The transverse size of the sink defect, relative to the sizeof the transverse domain, is important in determining the final pattern observed, and so, close tothreshold, standing waves are always observed.
Extraction Of Signals From Chaotic Laser Data, John B. Geddes, Kevin Short, Kelly Black
Extraction Of Signals From Chaotic Laser Data, John B. Geddes, Kevin Short, Kelly Black
John B. Geddes
Several experimental groups have demonstrated communication with chaotic lasers. We analyzedata collected from a message-modulated erbium-doped fiber-ring laser (provided by VanWiggerenand Roy). We show that the transmitted signal is dominated by convolution of the message with theresponse function of the laser. A simple model based on the topology of the laser allows us to recovera hidden message. While prior estimates indicate that the laser dynamics are high dimensional, weshow that only four parameters are required, each of which can be recovered from the transmittedsignal alone.
Bistability In A Simple Fluid Network Due To Viscosity Contrast, John B. Geddes, Brian D. Storey, David Gardner, Russell T. Carr
Bistability In A Simple Fluid Network Due To Viscosity Contrast, John B. Geddes, Brian D. Storey, David Gardner, Russell T. Carr
John B. Geddes
We study the existence of multiple equilibrium states in a simple fluid network using Newtonian fluids and laminar flow. We demonstrate theoretically the presence of hysteresis and bistability, and we confirm these predictions in an experiment using two miscible fluids of different viscosity—sucrose solution and water. Possible applications include blood flow, microfluidics, and other network flows governed by similar principles.