Ultrafast Laser Pulses for Structuring Materials at Micro/Nano Scale: From Waveguides to Superhydrophobic Surfaces

Abstract

Abstract:The current demand for fabricating optical and photonic devices displaying high performance, using low-cost and time-saving methods, prompts femtosecond (fs)-laser processing as a promising methodology. High and low repetition femtosecond lasers enable surface and/or bulk modification of distinct materials, which can be used for applications ranging from optical waveguides to superhydrophobic surfaces. Herein, some fundamental aspects of fs-laser processing of materials, as well as the basics of their most common experimental apparatuses, are introduced. A survey of results on polymer fs-laser processing, resulting in 3D waveguides, electroluminescent structures and active hybrid-microstructures for luminescence or biological microenvironments is presented. Similarly, results of fs-laser processing on glasses, gold and silicon to produce waveguides containing metallic nanoparticles, analytical chemical sensors and surface with modified features, respectively, are also described. The complexity of fs-laser micromachining involves precise control of material properties, pushing ultrafast laser processing as an advanced technique for micro/nano devices.

Towards the scale-up of the formation of nanoparticles on α-Ag2WO4 with bactericidal properties by femtosecond laser irradiation

“…When the material undergoes a higher laser fluence, a large number of electrons are pulled out of the material’s surface, thus forming an electronic cloud. This effect causes the remaining ions to leave the surface of the materials by electromagnetic attraction or inelastic collisions 51 , 52 . The cloud formed by hot electrons, ions and some other detached species form a plasma known as plasma plume, the life-time of which is in the order of nanoseconds 53 .…”

Micropatterning of poly(p‐phenylene vinylene) by femtosecond laser induced forward transfer

“…As the experiments were carried out at a scan speed of 100 µm s −1 , the number of pulses per spot is of the order of 250 000, which causes local heating responsible for the PPV transfer process. The heating is a consequence of a nonlinear absorption process along with the cumulative effect of high repetition rate lasers . Although the donor film is transparent to the wavelength, nonlinear absorption takes place only in the focal volume where the intensity is high enough to cause a nonlinear optical process, thus confining the laser material interaction to micrometer scales.…”

“…The components are vertically aligned in such a way as to direct the backside irradiation of the donor substrate toward the receptor, which is a conventional glass slide placed in contact with the PPV film. A schematic representation of our experimental set‐up is given in reference .…”

Trajectory generation and optimization for five-axis on-the-fly laser drilling: a state-of-the-art review

“…Other shapes of holes are also possible, such as rectangular and other complex geometries. [9][10][11] This paper focuses on trajectory planning for laser drilling of cylindrical holes in turbine engine components. This process occurs through melting and vaporization (also referred to as "ablation") of the work-piece material through absorption of energy from a focused laser beam.…”