2021, Volume 3, Issue 1
Helium ion beam (HIB) technology plays an important role in the extreme fields of nanofabrication. This paper reviews the latest developments in HIB technology as well as its extreme processing capabilities and widespread applications in nanofabrication. HIB-based nanofabrication includes direct-write milling, ion beam-induced deposition, and direct-write lithography without resist assistance. HIB nanoscale applications have also been evaluated in the areas of integrated circuits, materials sciences, nano-optics, and biological sciences. This review covers four thematic applications of HIB: (1) helium ion microscopy imaging for biological samples and semiconductors; (2) HIB milling and swelling for 2D/3D nanopore fabrication; (3) HIB-induced deposition for nanopillars, nanowires, and 3D nanostructures; (4) additional HIB direct writing for resist, graphene, and plasmonic nanostructures. This paper concludes with a summary of potential future applications and areas of improvement for HIB extreme nanofabrication technology.
Several detailed studies have comprehensively investigated the benefits and limitations of laser-assisted machining (LAM) of titanium alloys. These studies have highlighted the positive impact of the application of laser preheating on reducing cutting forces and improving productivity but have also identified the detrimental effect of LAM on tool life. This paper seeks to evaluate a series of the most common cutting tools with different coating types used in the machining of titanium alloys to identify whether coating type has a dramatic effect on the dominant tool wear mechanisms active during the process. The findings provide a clear illustration that the challenges facing the application of LAM are associated with the development of new types of cutting tools which are not subjected to the diffusion-controlled wear processes that dominate the performance of current cutting tools.
Integrating micro-optical components at the end facet of an optical fiber enables compact optics to shape the output beam (e.g. collimating, focusing, and coupling to free space elements or photonic integrated circuits). However, the scalability of this approach is a longstanding challenge as these components must be aligned onto individual fiber facets. In this paper, we propose a socket that enables easy slotting of fibers, self-alignment, and coupling onto micro-optical components. This integrated socket can be detached from the substrate upon fiber insertion to create a stand-alone optical system. Fabrication is done using nanoscale 3D printing via two-photon polymerization lithography onto glass substrates, which allows multiple sockets to be patterned in a single print. We investigated variations in socket design and evaluated the performance of optical elements for telecom wavelengths. We obtained an alignment accuracy of ~3.5 µm. These socket designs can be customized for high efficiency chip to fiber coupling and extended to other spectral ranges for free-form optics.