Conference Agenda

In the realm of astronomical scientific exploration, deployable and scalable approaches in space telescope systems are reshaping our understanding of the universe. Two revolutionary membrane-based space telescope designs, on-axis OASIS (Orbiting Astronomical Satellite for Investigating Stellar Systems) and off-axis SALTUS (Single Aperture Large Telescope for Universe Studies), have been developed as mid/far-infrared telescope concepts featuring an inflatable primary mirror. Through the scalable primary aperture design, these deployable space telescopes leverage an all-encompassing optical architecture that taps into the uncharted potential of extremely large telescope apertures. These visionary mission and optical designs pave the way for the next generation scalable telescopes of unprecedented dimensions and diffraction-limited imaging resolutions.

We present a mesh-based method for optimizing double-sided freeform lenses to control their caustic effects. Unlike traditional single-sided approaches, we optimize both sides of the lens simultaneously, using a bijective correspondence between the two sides to control light refraction paths. Our approach balances image fidelity, geometric compatibility, and physical constraints. Results demonstrate the method's capability to accurately produce intricate light patterns, opening new possibilities in optical applications.

We discuss an inverse method to compute a freeform two-reflector two-target system. The optical path length constitutes an integral component and can be expressed in terms of position coordinates at the first target. The system is expressed in terms of a generating function, closed with energy balance and requires a sophisticated least-squares solver to compute the shapes of the reflectors. In a numerical example, we illustrate the algorithm's capabilities to tackle even the most intricate light distributions.

The use of beam-based technologies to process optical elements with nanoscale precision enables the fabrication of freeform surfaces. In particular, atmospheric pressure plasma jets (APPJs) have desirable properties, e.g., depth precision < 5 nm, low surface roughness and processing at atmospheric conditions. However, the composition of optical glasses and glass ceramics, containing metal oxides, leads to the formation of non-volatile reaction products that remain on the substrate surface. These residues reduce the etching rate and cause severe roughening of the surface. Laser irradiation has already been demonstrated as a promising option for removing the residual layer and the aim of the current work is to integrate it into the APPJ system for simultaneous processing. Therefore, an excimer laser (λ = 248 nm; tPulse = 20 ns) with a maximum pulse frequency of 100 Hz was added to a plasma jet setup and experiments with varying laser fluences as well as laser frequencies were performed on N-BK7 substrates. White light interferometry was used to analyse the samples. The experiments showed an improved etching result with higher removal rates for the combined process at high laser pulse frequency (100 Hz) and fluences in the range of 0.1-0.45 J·cm-2.

The manufacturing of optical components is subject to constant efforts to optimise production processes in order to achieve high surface qualities under the most economical conditions possible. This includes the refinement of existing technologies or development of completely new production technologies. One possible approach is the combination of conventional machining processes for optical components like diamond turning, grinding or polishing with laser-based processes to thermally influence the surface for improved machining or surface properties. For this, knowledge of the thermal interactions of the laser on the component surface is needed, which in turn requires its metrological acquisition. In this work, measurements were carried out using various methods for the controlled heating of glass surfaces by an infrared laser (λ=1070 nm). Among other things, a clear correlation between the samples surface roughness and the laser absorption is found.