Use of 3D printing in astronomical mirror fabrication

In this paper we are exploring the possibilities of 3D printing in the fabrication of mirrors for astronomy. Taking the advantages of 3D printing to solve the existing problems caused by traditional manufacturing, two proof-of- concept mirror fabrication strategies are investigated in this paper. The first concept is a deformable mirror with...

Advanced light management techniques for two-terminal hybrid tandem solar cells

Multi-junction solar cells are considered for various applications, as they tackle various loss mechanisms for single junction solar cells. These losses include thermalization and non-absorption below the band gap. In this work, a tandem configuration comprising copper-indium-gallium-di-selenide (CIGS) and hydrogenated amorphous silicon (a-Si:H)...

Characterizing electron beam induced damage in metrology and inspection of advance devices

Microstructures of Early Jurassic (Toarcian) shales of Northern Europe

The Toarcian (Early Jurassic) Posidonia Shale Formation is a possible unconventional gas source in Northern Europe and occurs within the Cleveland Basin (United Kingdom), the Anglo-Paris Basin (France), the Lower Saxony Basin and the Southwest Germany Basin (Germany), and the Roer Valley Graben, the West Netherlands Basin, Broad Fourteens Basin,...

A brief review of environmentally benign antifouling and foul-release coatings for marine applications

Antifouling coatings for ship hulls are a very important topic in coating research. They are essential with respect to fuel consumption of ships: without antifouling coating, biological species start to adhere to the ship's exterior, leading to a gradual increase in fuel consumption. To date, the working principle of most of the paint systems...

Switchable static friction of piezoelectric composite-silicon wafer contacts

The meso-scale surface roughness of piezoelectric fiber composites can be manipulated by applying an electric field to a piezocomposite with a polished surface. In the absence of an applied voltage, the tips of the embedded piezoelectric ceramic fibers are below the surface of the piezocomposite and a silicon wafer counter surface rests solely...

Manufacturing of high precision aspherical and freeform optics

Aspherical and freeform optical elements have a large potential in reducing optical aberrations and to reduce the number of elements in complex high performance optical systems. However, manufacturing a single piece or a small series of aspherical and freeform optics has for long been limited by the lack of flexible metrology tools. With the...

Manufacturing of high precision aspherical and freeform optics

Aspherical and freeform optical elements have a large potential in reducing optical aberrations and to reduce the number of elements in complex high performance optical systems. However, manufacturing a single piece or a small series of aspherical and freeform optics has for long been limited by the lack of flexible metrology tools. With the...

Diamond turning and polishing tests on new RSP aluminium alloys

For years now conventional aluminium 6061 T6 has widely been used for mirrors in astronomical instruments, being diamond turned or since a few years also being optically polished. This allows the development of optical systems that can be tested and operated at any temperature, without being affected by CTE effects. Using traditional aluminium...

Accuracy of freeform manufacturing processes

The breakthrough of freeform optics is limited by manufacturing and metrology technology. However, today's manufacturing machines like polishing robots and diamond turning machines are accurate enough to produce good surface quality, so the question is how accurate can a freeform be produced. To investigate how accurate freeform optics can be...

In-process measurements of material removal in fluid jet polishing

A prototype of a system for in-process monitoring of material removal in fluid jet polishing (FJP) is presented. The measurements make use of temporal phase unwrapping (TPU) allowing for a large working range. The measurement system will be discussed, with all problems that had to be overcome like water on the surface and vibrations, as well as...

Applicability of iTIRM for roughness reduction monitoring

The results obtained with iTIRM during polishing are presented. It is shown that iTIRM unites the working ranges of several other techniques where iTIRM can be used during production where the others can not. The applicable range of iTIRM is shown to be at least 1 um down to 0.1 nm rms.

Production and measurement of superpolished surfaces

The influence of polishing time on the roughness of ultrasmooth bowl-feed-polished surfaces is studied. A large improvement of the surface quality is obtained within the first 10 minutes, but increasing the polishing time from 10 to 60 minutes did not yield a significant difference. A Linnik interference miscroscope, adapted for phase-shifting...