We have fabricated spherical and cylindrical concave micro-mirrors in silicon with dimensions from 20 microm to 100 microm. The fabrication process involves standard photolithography followed by large area ion beam irradiation and electrochemical anodisation in a HF electrolyte. After thermal oxidation the silicon surface roughness is less than 2 nm. We also present a multilayer porous silicon ...

K. Żak, W. Grzesik, M. Prażmowski, Opole University of Technology, Department of Manufacturing Engineering and Automation, Opole, Poland This paper presents a sequential machining process which incorporates CBN hard turning with cryogenic pre-cooling of the workpiece (CHT) and ball burnishing (BB). The main goal of this study was to select machining conditions enhancing the quality of parts mac...

Miniature concave hollows, made by wet etching silicon through a circular mask, can be used as mirror substrates for building optical micro-cavities on a chip. In this paper we investigate how ICP polishing improves both shape and roughness of the mirror substrates. We characterise the evolution of the surfaces during the ICP polishing using white-light optical profilometry and atomic force mic...

A wide range of opportunities are emerging in the micro-system technology sector for laser micro-machining systems, because they are capable of processing a various types of materials with micro-scale precision. However, few process datasets and machine learning techniques are optimized for this industrial task. This article aims to show how the process parameters of micro-laser milling influen...

The aerodynamic roughness is one of the major parameters in describing the turbulent exchange process between terrestrial and atmosphere. Remote Sensing is recognized as an effective way to inverse this parameter at the regional scale. However, in the long time the inversion method is either dependent on the lookup table for different land covers or the Normalized Difference Vegetation Index (N...

This paper discusses on the surface characteristics of each of the seven set-up process steps prior completion of under bump metallurgy (UBM) deposition. The Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) techniques were used to obtain the surface roughness and morphology of each deposition process. The elemental analysis using Energy Disperse X-Ray (EDX) and precision mic...

We compare measured profiles of upper layer shear and rates of kinetic energy dissipation with the predictions of a one-dimensional turbulence model proposed by Craig and Banner (1994). Their formulation contains an unknown parameter, the "roughness length" z0, which we determine by fitting computed and observed dissipation rates. The resulting model, without further adjustment, is then used to...

Optically pumped green lasing with an ultra low threshold has been achieved using an InGaN/GaN based micro-disk with an undercut structure on silicon substrates. The micro-disks with a diameter of around 1 μm were fabricated by means of a combination of a cost-effective silica micro-sphere approach, dry-etching and subsequent chemical etching. The combination of these techniques both minimises ...

Abstract Optimization of all the process parameters for laser powder bed fusion (L-PBF), considering effects individual on Ti6Al4V fabricated parts, can be complex and challenging. Therefore, first time, three main variable (laser power, scan speed, hatch spacing) outcomes (surface roughness, bulk porosity, production rate parts) were studied in this work. Then, combination above-mentioned form...