Two complementary ways of thin-metal-film patterning using laser beam interference and direct ablation

Abstract

Interference of several identical laser beams allows for the fabrication of periodical structures over large areas. We present two complementary techniques for the patterning of thin films using the laser beam interference and direct ablation of material. The first one is based on precise control of the laser fluence relative to the ablation threshold of the film. Additional means for pattern management are provided by separate control of the intensity and phase of the interfering laser beams. Interference of four or six laser beams permits fabrication of periodical arrays of circular holes. Flexibility and sensitivity to the process parameters of the method beyond of simple hole arrays are shown for the thin Cr film ablation. Another versatile means for pattern generation in the films is the scanning of the periodic laser beam distribution over a workpiece in a sub-period area. By translation of the sample in small steps between laser shots, the structures with their shape independent of the interfering beam intensity distribution can be fabricated by overlapping the ablated holes. Slit-and cross-shaped periodical structures were fabricated using direct structuring with interfering nanosecond and femtosecond pulses. The thin-film structures fabricated by both techniques can be used as spectrally-selective elements for terahertz and infrared radiation.

Direct and High-Throughput Fabrication of Mie-Resonant MetasurfacesviaSingle-Pulse Laser Interference

“…26,61 The irradiated material exhibits large temperature gradients and using the same interference pattern, but controlling the laser energy density with respect to the material damage threshold, we may obtain diverse patterns. 31,38 In case of thin films, the film-substrate interfacial free energy γ fs determines the shape of the surface. The morphology of isotropic films is defined by Youngs equation: 62,63 cos…”

“…To overcome this limitation and obtain high-throughput and cost-effectiveness, we propose the application of direct laser interference patterning. Direct patterning using high-peak-power laser interference has been previously shown as a suitable tool for large-area microstructuring of metals, [30][31][32][33][34][35][36][37][38][39] organic materials, [40][41][42] and even Si. [43][44][45][46][47][48][49][50] It does not require resist, etching or any other post-processing steps, thus is relatively fast and simple.…”

Biomimetic Surface Structuring Using Laser Based Interferometric Methods

“…DLIP has shown to be an outstanding technology for the processing of metallic surfaces. In the past, this technology has been applied a wide number of materials including aluminum, stainless steel, copper and titanium between others using nanosecond and picosecond pulsed laser systems [31][32][33][34][35].…”

Customizing plasmonic diffraction patterns by laser interference

“…Laser techniques for structuring metal surfaces involve direct laser writing or laser interference. 22,23 They are single-step processes, in which the laser induces transient heat that leads to melting of the thin lm and production of NPs by a fast melting/dewetting process. In a recent work, a great variety of plasmonic colours with high resolution has been produced by laser irradiation of periodic structures.…”