We demonstrate a fundamentally mode-locked Yb-doped “solid-state fiber laser” with a repetition rate of 1 GHz and a pulse duration of 48 fs. The nonlinear-polarization-evolution (NPE) mode-locking of ...the “solid-state fiber laser” enables up to 286 mW of average power and a 26 nm spectrum bandwidth, which supports a 48 fs pulse duration. The laser self-starts and the central wavelength can be tuned from 1032.4 nm to 1035.6 nm. To the best of our knowledge, it is the shortest pulse duration directly obtained by GHz fundamentally mode-locked Yb-fiber lasers.
In this paper, we report on laser patterned vacuum processed organic solar cells using an infrared ultra short pulse laser. Laser patterning is performed on all layers, electrodes as well as organic ...layers, to produce fast, reproducible, and precise scribes. The structuring enables monolithically interconnecting several cells to mini-modules. For patterning the silver top electrode, a plasma process is introduced which lowers the ablation threshold and minimizes protrusion-induced shunt formation. Finally, we demonstrate the up-scaling of organic mini-modules to an area of 64cm2 with a geometric fill factor of 94% and a power conversion efficiency on the aperture area of 4.3%.
•Laser patterning of all layers of an organic solar cell using a single ps-laser.•Protrusions (short-circuits) suppressed by oxygen plasma treatment of silver layer.•Fabrication of tandem mini-module with a PCE of 4.3% (area: 64cm2).
In this paper, we reviewed the scientific investigations of ultra-wideband supercontinuum (SC)generation with optical fibers. Thanks to the invention of photonic crystal fibers and highly ...nonlinearfibers, octave spanning supercontinuum can be generated with sub-nJ level ultrashort pulse pumping.Nowadays, we can generate coherent, low noise SC, which is useful for optical frequency comb, highresolutionoptical coherence tomography, etc. Historical background, generation mechanism, theirapplications, recent progress, and future prospects were briefly discussed.
•Ultrashort laser pulse causes strong foaming of irradiated metal.•Fast non-equilibrium re-crystallization freezes jets and undersurface nanobubbles.•After X-ray irradiation the surface ...nanostructures are created by foaming and freezing processes with no plasmonic effects.
Ultrashort laser pulse is a unique nanometallurgical tool which operates at extreme conditions: ultimate strength of material, the smallest spatiotemporal scales, and nonequlibrium crystallization. Approaches to ultimate strength and to highly nonequlibrium crystallization are tightly coupled with the smallness of spatiotemporal scales. Usage of the tool opens new opportunities to create materials with enhanced surface hardness, anticorrosion properties, and diverted optical constants. To use these advantages we have first of all to develop clear and reliable physical model. The paper presents new results concerning interactions of optical or X-ray lasers with metals. It is shown that ultrashort laser pulse melts surface layer, sends shock into bulk, and foams molten metal. Dense dislocation bilayer is created thanks to fast recrystallization (the first sublayer) and plastic transformations behind strong shock (the second sublayer). Plastic shock generated at moderate laser intensities attenuates sharply during its propagation into metal. During this attenuation, a plastic shock regenerates into a powerful elastic shock. This process defines boundary between the second dislocation sublayer and undamaged solid. Mechanical breaking of foam after its strong stretching and fly away of a part of melt together with fast freezing are responsible for appearance of chaotic frozen nanostructures at an irradiated surface.
Modeling laser beam as a tapered wave with a Gaussian spectrum, The temperature fields in HfO2/SiO2 high-reflection (HR) film, induced by 1ms long-pulse and 10ns short-pulse lasers, under different ...incident angles are calculated. The damage differences between long-pulse and short-pulse-induced damage in the HR film are analyzed. The results show for long-pulse laser, the temperature distribution is much less affected by the laser field effect than short-pulse case. Furthermore, as the irradiation angles increase from 0 to 35° for 1ms and 10ns lasers, the peak temperature rises in the HR film increase for s polarized laser. Other than long-pulse laser, for short-pulse laser, the positions of the peak temperature shift gradually toward the air–film interface as the incident angle increases, which may have a great influence on the position of thermal stress coupling and damage probability.
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