A nonlinear system with delayed feedback, whenever the delay time is much longer than intrinsic correlation time, displays two widely separated scales. In such a case, two-dimensional representation becomes appropriate, because it discloses features otherwise hidden in one-dimensional sequence of data, and allows use recognition algorithms developed for spatiotemporal chaos. As an illustration, chaotic sequences from single-mode laser feedback are analyzed using this representation.

We have carried out an investigation of the globally coupled laser array with randomly spread eigenfrequencies. It is shown that as this increases, either action vanishes or coherent steady-state regime replaced by a phase-unlocked regime. The regions stable phase locking been analytically and numerically determined. found gain inertia leads to cooperative phase-locking effects when maximum detuning close relaxation frequency.

We present an experimental and theoretical study of the dynamics a ${\mathrm{CO}}_{2}$ laser with delayed feedback. Working delay time such that its product bandwidth feedback loop yields number close to unity (so-called short-delay regime), we show evidence low-dimensional chaos, reached by destabilization two-dimensional torus (Curry-Yorke route chaos). A suitable model provides numerical solutions in agreement experiment. discuss under which conditions our system reduces Ikeda-type dynamics.

We report experimental evidence of a new type chaos characterized by pulses equal in shape, but irregularly separated time. The times return to Poincaré section are statistically spread, however their iteration map is one-dimensional and close agreement with that arising from Shil'nikov theory. Thus, the time intervals becomes most appropriate indicator this chaos. residual width experimentally measured maps due transient fluctuation enhancement peculiar macroscopic systems, which absent...

We present a study of Yb:YAG active media slabs, based on ceramic layered structure with different doping levels.We developed procedure allowing 3D numerical analysis the slab optical properties as consequence thermal load induced by pump process.The simulations are compared set experimental results in order to validate procedure.These structured ceramics appear promising appropriate geometrical configurations, and thus intended be applied construction High Energy Diode Pumped Solid State...

A CO2 laser with feedback shows different dynamic regimes depending on the dominant role of one or two three coexisting unstable stationary points. These have been characterized by statistical distributions return times to a Poincaré section at constant intensity. In particular, in regime Shil'nikov chaos iteration maps display spread owing transient fluctuation enhancement phenomenon peculiar macroscopic systems, which is absent low-dimensional chaotic dynamics.

The operation of a laser having both the advantages large area discharges and those arrays is reported. consists three parallel optical channels (slabs) with rectangular section. Locked emission due to distributed coupling slabs observed. resulting far-field pattern displays presence symmetric central lobe corresponding 2 Mrad divergence some residual sidelobes periodic structure in one transverse direction. Such can be handled by Talbot imaging techniques, scaled higher number channels.

We present the numerical and experimental study that we carried out to compare performances of two hybrid stable-unstable resonators for diffusion-cooled CO(2) slab lasers. The are designed fit a 320 mm × 60 ×2 rf-discharge channel both guided in narrow transverse direction. They differ other direction, consisting positive- or negative-branch unstable resonator scheme. solutions have been characterized terms modal structure, power extraction, stability, quality extracted beam.

Intercalated graphite materials allow studying reactions occurring in confined chemical conditions. In this work, we investigate the sulfuric acid intercalated exfoliation process using a simple technique based on continuous-wave (CW) infrared (IR) laser irradiation of flakes. Using Kissinger and Ozawa methods, activation energy H2SO4-intercalated was determined to be less than 100 kJ mol–1. The laser-assisted reaction found characterized by threshold temperature about 140 °C followed fast...

The reduction of the voltage variations along electrodes RF transversely excited CO/sub 2/ lasers is fundamental importance for attainment a uniform active medium pumping and consequent efficient laser power extraction. This problem has been studied by many authors in case narrow-channel waveguide methods have found to reduce relevant variation due transmission line effect determined discharge channel structure. In this paper, we demonstrate crucial role played electrode sheath's capacitance...

Diode pumped zig-zag slab lasers are widely adopted for continuous-wave high power or pulsed energy applications. Recently [J. Eur. Opt. Soc.-Rapid 6, 11041 (2011)] we started to investigate a new thin format in which pumping radiation input is obtained through the lateral faces (edge pumping) and beam propagation takes place bouncing on these same ("edge zig-zag"). We report optimized operation of ceramic Nd:YAG laser, based this geometry, extracting 230 W at 43% output diode conversion...

We present numerical simulations of the propagation field emitted by laser arrays consisting a small number elements. Our computations show how transforms part an amplitude modulation into phase modulation. This fact can be used to enhance central lobe energy in far high-power means simple corrective optical element. discuss optimal filtering conditions and prove that quarter-Talbot distance generally previous studies is not best choice.

With the help of photometric calculations based on ray-tracing algorithms, we have optimized efficiency optical pumping a Nd:YAG ceramic slab laser. The is performed by means two horizontal diode laser array stacks. use small reflecting walls allows sort duct coupling that capable significantly improving performance system. Our first experiments with simple direct provided maximum extraction slightly more than 160 W at 20% slope level. short leads us to 350 51%, making same arrays. design...

We describe our preliminary studies of the use neodymium-doped slab-shaped ceramic YAG media in construction compact, rugged, high-power diode-pumped solid-state lasers. A maximum extraction more than 160 W at a 20% slope efficiency level, with narrow transverse direction beam-parameter product order 4 mm mrad-1 is experimentally obtained from an extremely simple and compact (overall dimensions × 100 60 mm) laser head quasi-continuous-wave regime. Experimental data together finite-elements...

A new thin-slab ceramic Nd:YAG laser is presented based on a non-conventional zig-zag configuration. The slab shaped in such way that the beam propagates internally bouncing thin lateral faces (Edge zig-zag). Preliminary experiments have demonstrated power extraction of 170 W (CW) at an optical conversion efficiency 36%. Measurements also been performed to assess propagation properties, least thinner transverse direction, extracted with simple stable resonator. This format appears as good...

Slabs with non-uniform doping distribution are studied the aim of reducing thermal deformations in high-energy high-average-power Yb:YAG slab systems. We present a numerical analysis based on Finite Element Mesh (FEM) methods suitable to model devices. The variation refractive index, end-faces and photo-elastic effect have been calculated order estimate total thermal-lens effect. stress distributions also obtained. Some results this approach compared experimental lens measurements simple...

The laser, optical and spectroscopic properties of multilayer Yb:YAG ceramic structures, differently activated, were investigated. structures designed by means Finite Element Modeling, adjusting the doping distributions to reduce peak temperature, surface deformation thermally induced stresses, depending on pump cooling geometry. Two processes used, i.e. dry pressing spray-dried powders (SD) tape casting (TC), resulting in different defect density size distribution: TC gives a more uniform...

We have analyzed the propagation properties of field produced by circular arrays coherent optical sources, obtaining conditions for generation good-quality global beams. Such can be obtained use resonators based on Talbot effect. This appears to a practical method construction simple, low-cost compact diffusion-cooled high-power lasers with annular format. Low-loss cavity configurations also been studied.