TIME AVERAGING OF IRREGULAR SPATIOTEMPORAL PATTERNS OF A LARGE APERTURE LASER IN TRANSITORY REGIME

2001 ◽  
Vol 11 (06) ◽  
pp. 1771-1779
Author(s):  
F. ENCINAS-SANZ ◽  
I. LEYVA ◽  
J. M. GUERRA
Keyword(s):  
Experimental Technique ◽  
Exposure Time ◽  
Time Integration ◽  
Spatiotemporal Patterns ◽  
Time Averaging ◽  
Bloch Equations ◽  
Ordered Structures ◽  
Large Aperture ◽  
Spatiotemporal Behavior ◽  
Maxwell Bloch Equations

By means of a new experimental technique, we measure quasi-intantaneous transverse intensity patterns in the gain-switch peak of a transversely excited atmospheric CO 2 laser with large aperture. The patterns recorded with a 2 ns resolution show a completely irregular spatiotemporal behavior, but when the exposure time of the measurements increases, boundary-determined ordered structures can be observed. As a quantification of this averaging process, the contrast of the intensity distributions decreases as the time integration grows. The results are numerically reproduced by integration of the full Maxwell–Bloch equations.

Numerical solutions to 2D Maxwell–Bloch equations

2008 ◽  
Vol 40 (5-6) ◽  
pp. 447-453 ◽  
Author(s):  
Jingyi Xiong ◽  
Max Colice ◽  
Friso Schlottau ◽  
Kelvin Wagner ◽  
Bengt Fornberg
Keyword(s):  
Numerical Solutions ◽  
Bloch Equations ◽  
Maxwell Bloch Equations

A Non-Intrusive Experimental Technique for Constructing Poincaré Maps in 3D Chaotically Advected Flows

2001 ◽  
Author(s):  
Fotis Sotiropoulos ◽  
Igor Mezić ◽  
Donald R. Webster
Keyword(s):  
Light Intensity ◽  
Experimental Technique ◽  
Vortex Breakdown ◽  
Laser Sheet ◽  
Three Dimensional ◽  
Chaotic Advection ◽  
Time Averaging ◽  
Poincaré Maps ◽  
Poincare Maps ◽  
The Rich

Abstract We propose and develop the theoretical framework for a new experimental technique for constructing Poincaré maps in three-dimensional flows exhibiting chaotic advection. The technique is non-intrusive and, thus, simple to implement. Planar laser-induced fluorescence (LIF) is employed to collect a sufficiently long sequence of instantaneous light intensity fields on the plane of section of the Poincaré map (defined by the laser sheet). The chains of unmixed (regular) islands in the flow are visualized by time-averaging the instantaneous images and plotting iso-contours of the resulting mean light intensity field. A rigorous theoretical justification for this technique is derived using concepts from ergodic theory. We demonstrate the capabilities of the method by applying it to visualize the rich Lagrangian dynamics within steady vortex breakdown bubbles in a closed cylinder with a rotating bottom. The experimental results are shown to be in excellent agreement with numerical simulations.

Exposure Time Control of Large Aperture Static Imaging Spectrometer

2015 ◽  
Vol 44 (11) ◽  
pp. 1123004
Author(s):  
杨阳 YANG Yang ◽  
刘学斌 LIU Xue-bin
Keyword(s):  
Exposure Time ◽  
Imaging Spectrometer ◽  
Large Aperture ◽  
Time Control ◽  
Static Imaging

LIE–TROTTER FORMULA AND POISSON DYNAMICS

1999 ◽  
Vol 09 (03) ◽  
pp. 555-559 ◽  
Author(s):  
MIRCEA PUTA
Keyword(s):  
Rigid Body ◽  
Euler Equations ◽  
Bloch Equations ◽  
Free Rigid Body ◽  
Trotter Formula ◽  
Maxwell Bloch Equations

We construct via the Lie–Trotter formula some explicit Poisson integrators for the Maxwell–Bloch equations from laser-matter dynamics, the Euler equations of the free rigid body and the equations of the rigid body with a spinning rotor.

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