Progress In Fabrication Technology Research Articles

Physical Information-Embedded Deep Learning for Forward Prediction and Inverse Design of Nanophotonic Devices

Nanophotonic devices have enabled electromagnetic manipulation with unprecedented accuracy and functionalities. With the increased functionality requirements of such devices and the progress of fabrication technologies, trends toward miniaturization and multi-functionality have emerged, making forward response prediction and inverse design increasingly complicated. In this paper, a physical information-embedded deep learning model for flexible forward prediction and multifunctional inverse design is proposed. Besides the overwhelming advantage of computing efficiency over conventional iterative optimization methods, the proposed method exhibits strong generalization on different wavelengths and polarizations by embedding the corresponding physical information into the model through effective sparse parameter method (SPM). For the forward prediction, responses can be predicted among the 1300-1550 nm wavelength band and two polarizations (TM/TE) with high accuracy. For the inverse design, with the assistance of forward prediction models and broadband training methods, multi-dimensional information for the target can be considered simultaneously to retrieve the satisfactory desired designs topologies in an unsupervised way. The multi-functionality of inverse design is demonstrated by implementing wavelength demultiplexers with small crosstalk and power splitters with arbitrary splitting ratios on a 250 nm broadband wavelength in a compact footprint of 2 × 2 μm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> without additional heavy training of the model.

Diamond diffractive optics—recent progress and perspectives

Abstract Diamond is an exceptional material that has recently seen a remarkable increase in interest in academic research and engineering since high-quality substrates became commercially available and affordable. Exploiting the high refractive index, hardness, laser-induced damage threshold, thermal conductivity and chemical resistance, an abundance of applications incorporating ever higher-performance diamond devices has seen steady growth. Among these, diffractive optical elements stand out—with progress in fabrication technologies, micro- and nanofabrication techniques have enabled the creation of gratings and diffractive optical elements with outstanding properties. Research activities in this field have further been spurred by the unique property of diamond to be able to host optically active atom scale defects in the crystal lattice. Such color centers allow generation and manipulation of individual photons, which has contributed to accelerated developments in engineering of novel quantum applications in diamond, with diffractive optical elements amidst critical components for larger-scale systems. This review collects recent examples of diffractive optical devices in diamond, and highlights the advances in manufacturing of such devices using micro- and nanofabrication techniques, in contrast to more traditional methods, and avenues to explore diamond diffractive optical elements for emerging and future applications are put in perspective.

Focused Ion Beam Lithography to Etch Nano-architectures into Microelectrodes.

With advances in electronics and fabrication technology, intracortical microelectrodes have undergone substantial improvements enabling the production of sophisticated microelectrodes with greater resolution and expanded capabilities. The progress in fabrication technology has supported the development of biomimetic electrodes, which aim to seamlessly integrate into the brain parenchyma, reduce the neuroinflammatory response observed after electrode insertion and improve the quality and longevity of electrophysiological recordings. Here we describe a protocol to employ a biomimetic approach recently classified as nano-architecture. The use of focused ion beam lithography (FIB) was utilized in this protocol to etch specific nano-architecture features into the surface of non-functional and functional single shank intracortical microelectrodes. Etching nano-architectures into the electrode surface indicated possible improvements of biocompatibility and functionality of the implanted device. One of the benefits of using FIB is the ability to etch on manufactured devices, as opposed to during the fabrication of the device, facilitating boundless possibilities to modify numerous medical devices post-manufacturing. The protocol presented herein can be optimized for various material types, nano-architecture features, and types of devices. Augmenting the surface of implanted medical devices can improve the device performance and integration into the tissue.

Update 2017 on Target Fabrication Requirements for High-Performance NIF Implosion Experiments

Experiments and analysis in the 2 years since the 2015 Target Fabrication Meeting have resulted in further evolution of the requirements for high-performance layered implosions. This paper is a status update on the experimental program and supporting modeling, with emphasis on the implications for fabrication requirements. Previous work on the capsule support has continued, with various other support options being explored in experiments and modeling. Work also continues on ablator composition nonuniformities, with important new results from CH experiments on Omega, and the first three-dimensional X-ray transmission measurements of Be capsules on the National Ignition Facility. Work on hohlraums continues to include near-vacuum hohlraums and U hohlraums without a gold lining. Overall, the understanding that has been achieved, along with the progress in fabrication technology, represents good continuing progress toward the goal of fusion in the laboratory.

Flexible and Rapid Measurement

AbstractOnly what you can measure, you can produce. This often quoted statement aptly describes the area of aspheric lenses production in its interplay of progress in fabrication technology and metrology. Nowadays not only the pure feasibility is in focus, but also economical factors: higher flexibility, high measurement speed and high lateral resolution, ideally all combined with a low measurement uncertainty. In this context, we discuss the recently proposed tilted wave interferometer (TWI, Fig. 1), an approach to interferometrically measure steep aspheres and freeforms within a few seconds.

Wearable textile antennas

Owing to the rapid progress in fabrication technologies of conductive fibrous materials and the increasing demand for wireless communications in smart clothing systems, the potential application of wearable textile antennas in this field continues to increase. This article reviews a variety of wearable textile antennas in order to provide background information and application ideas for designing such antennas. The various materials used in the construction of wearable textile antennas, their fabrication methods, as well as the antenna types and their application fields are summarised. Owing to the high conductivity of metals, various metal composite yarns (MCYs) and fabrics have been used in the production of textile antennas. For inductively coupled near-field communication within smart clothing systems, woven or embroidered multiturn loop antennas are suggested. For far-field communication, a variety of broadband textile antennas were developed to counterbalance the detuning caused by the presence of a human body. Embroidered-folded dipole array antennas, metal-coated fabric patched bowtie and spiral antennas, a microstrip patch antenna array and a coplanar antenna made of metal-coated fabric patches and a ground plane, are the antennas that cover a broad spectrum and thus are capable of operating on the body.

Integrated nano-structured silicon waveguides and devices for high-speed optical communications (Invited Paper)

With progress in fabrication technology, integrated photonics plays an increasingly important role in highspeed optical communications, from monolithic transmitters and receivers for advanced optical modulation formats to on-chip subsystems for optical signal processing. We review our recent work on the highly tailorable physical properties of silicon waveguides for communication and signal processing applications, using slot structures. Controllable chromatic dispersion, nonlinearity, and polarization properties of the waveguides are presented, and the enabled wideband wavelength conversion, optical tunable delay, and signal processing of polarization-multiplexing data channels are discussed.

High-temperature Fiber Matrix Composites for Reduction of Radiation Heat Transfer

AbstractRecent progress in fabrication technology allows for the efficient control of electromagnetic waves by means of photonic devices. This could be attractive and promising also for high-temperature photonic structures to control electromagnetic heat transfer at temperatures above 1000 oC. We discuss the literature and present our own results on Fiber Matrix Composites (FMC), which could be superior to high-temperature metals or monolithic ceramics and can be designed for photonic applications. Possible applications include the protection of non-rotating components in high-temperature engines and turbines such as combustors and liners, coatings and parts for aerospace vehicles. Our discussion includes the material aspect and some relevant structure features. The use of woven fabrics to design new photonic band gap structures is discussed. An example of the use of the plane-wave expansion method for FMC design is given.

Vanadium Alloys for Fusion Blanket Applications

Vanadium alloys are attractive candidate structural materials for breeding blanket of fusion reactors because of their low activation properties and high temperature strength. Studies on various blanket designs are being carried out using vanadium alloys as structural materials and liquid lithium or molten salt Flibe as breeding and coolant materials. Recently significant progress in fabrication technology has been made for vanadium alloys through a program of producing large ingots of high purity V-4Cr-4Ti (NIFS-HEATs). Fundamental understandings on the effects of interstitial impurities (C, N, O) on mechanical properties, radiation effects on microstructure and mechanical properties, corrosion and compatibility in various environments were enhanced. New promising candidates were identified for the MHD insulator coating. Among the remaining critical issues are the effects of transmutant helium on mechanical properties and development of long life MHD coating. Development of vanadium alloys will he carried out in coordination with IFMIF and ITER-TBM schedules as essential tools for verification of their performance in fusion blanket environments.

Microwave performance evaluation of diamond surface channel FETs

Diamond is expected to become an important semiconductor for high power and high frequency applications. Recent progress in fabrication technology has enabled DC, small signal RF, large signal RF and switching experiments on devices with short gatelength leading to the first comprehensive assessment of the performance capability of these devices. Using high-quality diamond buffer layers the highest cut-off frequencies for L G=0.2 μm namely f T=24.6 GHz, f max(MAG)=63 GHz and f max(U)=80 GHz could be extracted from small signal measurements near the pinch-off region. First noise measurements have resulted in a minimum noise figure F min of approximately 1 dB at 3 GHz. Power measurement at 1 GHz indicate a saturated output power density of 0.35 W/mm, which is, however, limited by the on-wafer tuning range.

Applications of Shape Memory Alloys in Japan

In Japan, a first application of shape memory TiNi alloy was a moving flap in an air-conditioner which was developed as sensing function of shape memory alloy at Matsushista Electric Industrial Co., Then, shape memory utilized in a coffee maker, an electric rice-cooker, a thermal mixing valve and etc. were commercialized in Japan. And brassiere wires, a guide wire for medical treatment, an antenna for portable telephone and others were commercialized utilizing superelasticity. At the same time with these commercial products, there was not only progress in fabrication technology to effect accurate transformation temperature, but also the discovery of small hysteresis alloy such as R-phase or TiNiCu alloy and low transformation temperature alloy such as TiNiFe, TiNiV and TiNiCo alloys. Therefore the shape memory alloy market has expanded widely to electric appliances, automobile, residence, medical care and other field today.

Technological and productive innovations in the ceramic industry with particular reference to ceramic floor and wall tiles

A review is made of the more important innovations relative both to fabrication technology (in particular as regards the phases of raw materials preparation, drying and firing) and to the quality and performance of products introduced recently by the ceramic floor and wall tile industry. The description of the innovative solutions regarding machinery and equipment is accompanied by a discussion and characterization of the advantages, which result from their introduction, for quality of the semiworked pieces and final products as well as for the optimization of energy consumption and management of the processes as compared with traditional technology. The picture that emerges provides a precise detailed outline of the evolutional trends in a sector, that of ceramic floor and wall tile, in which Italy holds an important and stable position of leadership, not only in production capacity but also in progress in fabrication technology and the attainment of higher levels of quality.