TY - CHAP A1 - Vorholt, Christian A1 - Wittrock, Ulrich T1 - Wavelength control by angle-tuning of the laser radiation in an intra-cavity pumped Yb:YAG thin-disk laser T2 - Advanced Solid State Lasers (ASSL), paper AM5A.39 N2 - In an intra-cavity pumped thin-disk laser the pump radiation forms a standing wave pattern inside the intra-cavity pumped disk.We demonstrate experimentally that the grating period of the standing wave pattern of the pump radiation can control the laser wavelength. Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:836-opus-8298 UR - https://www.osapublishing.org/abstract.cfm?uri=ASSL-2015-AM5A.39 ER - TY - CHAP A1 - Leitz, Sinje A1 - Gerhards, Maximilian A1 - Verpoort, Sven A1 - Wittrock, Ulrich A1 - Freudling, Maximilian A1 - Grzesik, Andreas A1 - Erhard, Markus A1 - Hallibert, Pascal T1 - Vibration and shock testing of a 50 mm aperture unimorph deformable mirror T2 - Proceedings of the International Conference on Space Optics (ICSO) N2 - We present our latest results on a refined unimorph deformable mirror which was developed in the frame of the ESA GSTP activity ”Enabling Technologies for Piezo-Based Deformable Mirrors in Active Optics Correction Chains”. The identified baseline concept with the soft piezoceramic material PIC151 successfully sustained all vibration requirements (17.8 gRMS random and 20 g sine) and shock testing (300 g SRS). We cover the mirror design development which reduces the stress in the brittle piezo-ceramic by 90 % compared to the design from a former GSTP activity. We briefly address the optical characterization of the deformable mirror, namely the achieved Zernike amplitudes as well as the unpowered surface deformation (1.7 µm) and active flattening (12.3 nmRMS). The mirror produces low-order Zernike modes with a stroke of several tens of micrometer over a correction aperture of 50 mm, which makes the mirror a versatile tool for space telescopes. KW - active optics KW - adaptive optics KW - deformable mirror KW - vibration damping KW - space telescopes Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:836-opus-137401 UR - https://icso2020.com/ VL - 11852 SP - 118524N ER - TY - CHAP A1 - Rausch, Peter A1 - Verpoort, Sven A1 - Wittrock, Ulrich T1 - Unimorph piezoelectric deformable mirrors for space telescopes T2 - Space Telescopes and Instrumentation 2016: Optical, Infrared, and Millimeter Wave, Proc. SPIE N2 - We have developed, manufactured and tested a unimorph deformable mirror for space applications based on piezoelectric actuation. The mirror was designed for the correction of low-order Zernike modes with a stroke of several tens of micrometers over a clear aperture of 50 mm. It was successfully tested in thermal vacuum, underwent lifetime tests, and was exposed to random vibrations, sinusoidal vibrations, and to ionizing radiation. We report on design considerations, manufacturing of the mirror, and present the test results. Furthermore, we discuss critical design parameters, and how our mirror could be adapted to serve recently proposed space telescopes such as HDST and TALC. Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:836-opus-9230 VL - 9904 SP - 990468 ER - TY - CHAP A1 - Verpoort, Sven A1 - Wittrock, Ulrich T1 - Unimorph deformable mirror for telescopes and laser applications in space T2 - International Conference on Space Optics (ICSO), Rhodes Island, Greece N2 - Over the past 5 years we have developed a new type of unimorph deformable mirror. The main advantages of this mirror technology are · very low surface scattering due to the use of superpolished glass · excellent coatings, even suitable for high power lasers, can be applied · active diameter of the mirrors can be between 10 mm and 100 mm · large strokes can be achieved even for small mirror diameters · integrated monolithic tip/tilt functionality based on a spiral arm design We have modeled these mirrors by analytical models as well as by the finite element method. This allows us to quickly design new mirrors tailored to specific applications. One example is a mirror for laser applications that has a diameter of 10 mm and can achieve a stroke in defocus mode of 5 μm. The stroke for these mirrors scales as the square of the mirror diameter, meaning that we can achieve, for example, a stroke of 125 μm for a mirror of 50 mm diameter. We will present design criteria and tradeoffs for these mirrors. We characterize our mirrors by the maximum stroke they can deliver for various Zernike modes, under the boundary condition that the Zernike mode has to be created with a certain fidelity, usually defined by the Maréchal criterion. Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:836-opus-6484 UR - www.icsoproceedings.org PB - SPIE ER - TY - CHAP A1 - Durand, G. A1 - Amiaux, J. A1 - Sauvage, M. A1 - Austin, J. A1 - Chesne, S. A1 - Collette, C. A1 - Helgouashl, S. A1 - Pareschi, J. A1 - Penfornis, Y. A1 - Valsecchi, G. A1 - Wittrock, U. T1 - TALC a far-infrared 20m space telescope and the ELICSIR consortium to reach TRL 3 T2 - Proceedings of the 37th ESA Antenna Workshop, Noordwijk, Netherlands N2 - Further space exploration in the far-infrared (FIR) requires larger apertures in order to improve the spatial resolution of captured images. To this purpose, the Thinned Aperture Light Collector (TALC) concept of a deployable annular telescope has been recently developed at CEA, which offers novel perspectives for FIR space missions. The consortium ELICSIR consortium of European institutes and companies has been created to improve the technological readiness level (TRL) of its key systems and components. Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:836-opus-9253 UR - http://esaconferencebureau.com/2016-events/16c18/introduction ER - TY - CHAP A1 - Freudling, Maximilian A1 - Grzesik, Andreas A1 - Erhard, Markus A1 - Gerhards, Maximilian A1 - Leitz, Sinje A1 - Verpoort, Sven A1 - Wittrock, Ulrich A1 - Hallibert, Pascal T1 - Space-qualified piezo based deformable mirror for future instruments with active optics T2 - Proceedings of the International Conference on Space Optics (ICSO) N2 - This paper presents the results of the technology development project “Enabling Technologies for Piezo-Based Deformable Mirrors in Active Optics Correction Chains” conducted by OHB System AG together with its partner Münster University of Applied Sciences (MUAS). The project was funded by ESA within their General Support Technology Programme (GSTP). We address in this paper mainly the definition, flow-down and verification of the requirements for the Deformable Mirror (DM). The requirements were derived from a set of real space mission applications. The deformation of the mirror is performed by piezo-ceramic actuators in an unimorph configuration. The finally developed DM is able produce Zernike modes with a stroke of several tens of µm over a clear optical aperture of 50 mm in diameter. It underwent successfully a full environmental qualification campaign including thermal cycling, shock- and vibration testing, as well as exposure to proton and γ–ray radiation. Thermal and performance tests were performed in the temperature range from 100 K to 300 K. Furthermore, the DM sustained all vibration (random 17.8 g RMS and sinus) and shock (300 g) testing. Thereby all criticalities which were identified a previous study have been overcome successfully. A Technology Readiness Level (TRL) of 5 is reached, as the component has been validated in relevant environment. Based on the high level of maturity, this deformable mirror is now ready for the incorporation in future flight instruments. The achieved TRL of 5 is sufficient for the status of a PDR at payload level and gives thus a very good basis for all kinds of potential B2, C/D payload developments. KW - deformable mirror KW - active optics KW - space qualification KW - space telescopes KW - adaptive optics Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:836-opus-137410 UR - https://www.spiedigitallibrary.org/conference-proceedings-of-spie/11852/1185231/Space-qualified-Piezo-Based-Deformable-Mirror-for-future-Instruments-with/10.1117/12.2599467.full VL - 11852 SP - 1185231-11 ER - TY - CHAP A1 - Rausch, Peter A1 - Verpoort, Sven A1 - Wittrock, Ulrich T1 - Performance verification and environmental testing of a unimorph deformable mirror for space applications. T2 - Proceedings of the 10th International Conference on Space Optics - ICSO, Tenerife, Spain N2 - Concepts for future large space telescopes require an active optics system to mitigate aberrations caused by thermal deformation and gravitational release. Such a system would allow on-site correction of wave-front errors and ease the requirements for thermal and gravitational stability of the optical train. In the course of the ESA project "Development of Adaptive Deformable Mirrors for Space Instruments" we have developed a unimorph deformable mirror designed to correct for low-order aberrations and dedicated to be used in space environment. We briefly report on design and manufacturing of the deformable mirror and present results from performance verifications and environmental testing. KW - space optics KW - adaptive optics KW - deformable mirror KW - unimorph Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:836-opus-7716 UR - http://www.icsoproceedings.org PB - FH Münster ER - TY - CHAP A1 - Verpoort, Sven A1 - Wittrock, Ulrich T1 - Novel unimorph deformable mirror with monolithic tip-tilt functionality for solid state lasers T2 - MEMS Adaptive Optics V, Proc. SPIE N2 - We present a new type of unimorph deformable mirror with monolithic tip-tilt functionality. The tip-tilt actuation is based on a spiral arm design. The mirror will be used in high-power laser resonators for real-time intracavity phase control. The additional tip-tilt correction with a stroke up to 6 μm simplifies the resonator alignment significantly. The mirror is optimized for a laser beam footprint of about 10 mm. We have modeled and optimized this mirror by finite element calculations and we will present design criteria and tradeoffs for this mirrors. The mirror is manufactured from a super-polished glass substrate with very low surface scattering and excellent dielectric coating. Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:836-opus-6471 VL - 7931 SP - 793107 PB - SPIE ER - TY - CHAP A1 - Verpoort, Sven A1 - Rausch, Peter A1 - Wittrock, Ulrich T1 - Novel unimorph deformable mirror for space applications T2 - International Conference on Space Optics (ICSO), Proc. SPIE N2 - We have developed a new type of unimorph deformable mirror, designed to correct for low-order Zernike modes. The mirror has a clear optical aperture of 50 mm combined with large peak-to-valley Zernike amplitudes of up to 35 μm. Newly developed fabrication processes allow the use of prefabricated super-polished and coated glass substrates. The mirror's unique features suggest the use in several stronomical applications like the precompensation of atmospheric aberrations seen by laser beacons and the use in woofer-tweeter systems. Additionally, the design enables an efficient correction of the inevitable wavefront error imposed by the floppy structure of primary mirrors in future large space-based telescopes. We have modeled the mirror by using analytical as well as finite element models. We will present design, key features and manufacturing steps of the deformable mirror. Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:836-opus-6516 UR - https://www.spiedigitallibrary.org/conference-proceedings-of-spie/10564/1056414/Novel-unimorph-deformable-mirror-for-space-applications/10.1117/12.2309089.full VL - 10564 SP - 1056414-1 PB - SPIE ER - TY - CHAP A1 - Verpoort, Sven A1 - Welp, Petra A1 - Wittrock, Ulrich T1 - Novel unimorph deformable mirror for solid state laser resonators T2 - MEMS Adaptive Optics III, Proc. SPIE N2 - We present a novel unimorph deformable mirror with a diameter of only 10 mm that will be used in adaptive resonators of high power solid state lasers. The relationship between applied voltage and deformation of a unimorph mirror depends on the piezoelectric material properties, layer thicknesses, boundary conditions, and the electrode pattern. An analytical equation for the deflection of the piezoelectric unimorph structure is derived, based on the electro-elastic and thin plate theory. The validity of the proposed analytical model has been proven by numerical finite-element modelling and experimental results. Our mirror design has been optimized to obtain the highest possible stroke and a high resonance frequency. Y1 - 2009 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:836-opus-6504 VL - 72090N PB - SPIE ER -