Conference Agenda

This study presents a manufacturing approach for a miniaturised optical element with three zonally separated aspherical surface regions, using CNC grinding. The optic serves as the refractive component of a hybrid multifocal imaging system, where each aspherical zone provides a distinct focal distance. Key challenges of the manufacturing process include the small aperture size, form tolerances, and the zonal boundary transitions.

Mirrors made of aluminum alloys are typically manufactured using

single-point diamond turning or fly-cutting. Although both methods achieve

good surface roughness, they leave tool marks that limit the use of aluminum

alloy mirrors in the ultraviolet and visible light ranges. In addition, they cause

geometric errors that reduce efficiency even in infrared applications. This study

presents two ion beam processes designed to overcome these limitations. Reactive

ion beam figuring is used to correct the figure error from 26.3 nm rms

to 8.9 nm rms (S10z = 354 nm to S10z = 84 nm) without increasing microroughness,

while ion beam planarization is used to reduce tool marks by more

than 70% to 0.6 nm rms.

High-performance optical systems for laser fusion, satellite communication terminals, or gravitational wave interferometry require optical coatings with total losses in the few parts-per-million (ppm) range. While surface roughness and form errors are well controlled in state-of-the-art fabrication, residual defects, particulate contamination, and coating microstructure ultimately govern the performance. A characterization methodology combining high sensitive absorption, angle-resolved scattering (ARS/BRDF), and residual reflectance/transmittance measurement is presented. The method resolves the complete energy balance and supports targeted process optimization. Exemplary results demonstrate both the achievable performance levels and the diagnostic capability of the approach.

Direct bonding provides a powerful manufacturing route for advanced optical systems, enabling mechanically robust, optically high‑quality, and highly precise assemblies. This contribution focuses on lessons learned and practical manufacturing constraints derived from the fabrication of directly bonded optical components ranging from wafer‑level structures to large, stiff optical geometries. Bond strengths of up to 80 % of the bulk material were achieved, demonstrating the suitability of direct bonding as a structural and optical joining technology even under harsh environmental conditions such as vacuum, radiation exposure, and high optical power. Optical characterization revealed negligible residual reflection and no refractive index discontinuity at the interface when bonding identical materials such as fused silica. At the same time, the results highlight critical constraints: surface quality, form accuracy, and bonding-induced stress influence achievable optical performance and yield. The process enables sub‑micrometer alignment accuracy, supports curved interfaces, and allows the use of pre‑applied optical coatings, including on internal surfaces. Based on experimental results, design guidelines and fabrication constraints are discussed, providing practical insight into how direct bonding can be integrated into optical system design for applications including space optics, high‑power lasers, quantum technologies, and gravitational wave detection.