@incollection{VerpoortWittrock2009, author = {Verpoort, Sven and Wittrock, Ulrich}, title = {Miniaturized adaptive mirror for solid state laser resonators}, series = {Proceedings of the 7th International Workshop on Adaptive Optics for Industry and Medicine, Shatura, Russia}, booktitle = {Proceedings of the 7th International Workshop on Adaptive Optics for Industry and Medicine, Shatura, Russia}, year = {2009}, language = {en} } @inproceedings{VerpoortWelpWittrock2009, author = {Verpoort, Sven and Welp, Petra and Wittrock, Ulrich}, title = {Novel unimorph deformable mirror for solid state laser resonators}, series = {MEMS Adaptive Optics III, Proc. SPIE}, volume = {72090N}, booktitle = {MEMS Adaptive Optics III, Proc. SPIE}, publisher = {SPIE}, doi = {10.25974/fhms-650}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:836-opus-6504}, year = {2009}, abstract = {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.}, language = {en} } @inproceedings{VerpoortWittrock2010, author = {Verpoort, Sven and Wittrock, Ulrich}, title = {Unimorph deformable mirror for telescopes and laser applications in space}, series = {International Conference on Space Optics (ICSO), Rhodes Island, Greece}, booktitle = {International Conference on Space Optics (ICSO), Rhodes Island, Greece}, publisher = {SPIE}, doi = {10.25974/fhms-648}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:836-opus-6484}, year = {2010}, abstract = {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 Mar{\´e}chal criterion.}, language = {en} } @article{VerpoortWittrock2010, author = {Verpoort, Sven and Wittrock, Ulrich}, title = {Actuator patterns for unimorph and bimorph deformable mirrors}, series = {Appl. Opt.}, volume = {49}, journal = {Appl. Opt.}, publisher = {OSA}, doi = {10.25974/fhms-649}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:836-opus-6490}, pages = {G37 -- G46}, year = {2010}, abstract = {The actuator pattern of an adaptive mirror determines the amplitudes and the fidelities of the mirror deformations that can be achieved. In this study, we analyze and compare different electrode patterns of piezoelectric unimorph deformable mirrors using a numerical finite element model. The analysis allows us to determine the optimum actuator pattern, and it is also applicable to bimorph mirrors. The model is verified by comparing its predictions with experimental results of our prototype of a novel unimorph deformable mirror.}, language = {de} } @inproceedings{VerpoortWittrock2011, author = {Verpoort, Sven and Wittrock, Ulrich}, title = {Deformable mirrors for high power lasers}, series = {Proceedings of the 8th International Workshop on Adaptive Optics for Industry and Medicine (AOIM)}, booktitle = {Proceedings of the 8th International Workshop on Adaptive Optics for Industry and Medicine (AOIM)}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:836-opus-106953}, year = {2011}, abstract = {It has been shown that the beam quality and the efficiency of high-power solid-state lasers could be enhanced by the use of deformable mirrors in order to compensate for optical aberrations. An intracavity compensation requires a deformable mirror which is capable of handling very high laser intensities. The active diameter of the deformable mirror should be a few millimeters in order to match typical fundamental mode laser beam diameters. There is a wide variety of commercially available deformable mirrors, but neither meets all requirements.}, language = {en} } @inproceedings{VerpoortWittrock2011, author = {Verpoort, Sven and Wittrock, Ulrich}, title = {Novel unimorph deformable mirror with monolithic tip-tilt functionality for solid state lasers}, series = {MEMS Adaptive Optics V, Proc. SPIE}, volume = {7931}, booktitle = {MEMS Adaptive Optics V, Proc. SPIE}, publisher = {SPIE}, doi = {10.25974/fhms-647}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:836-opus-6471}, pages = {793107}, year = {2011}, abstract = {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.}, language = {en} } @inproceedings{VerpoortRauschWittrock2012, author = {Verpoort, Sven and Rausch, Peter and Wittrock, Ulrich}, title = {Novel unimorph deformable mirror for space applications}, series = {International Conference on Space Optics (ICSO), Proc. SPIE}, volume = {10564}, booktitle = {International Conference on Space Optics (ICSO), Proc. SPIE}, publisher = {SPIE}, doi = {10.25974/fhms-651}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:836-opus-6516}, pages = {1056414-1}, year = {2012}, abstract = {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.}, language = {en} } @inproceedings{RauschVerpoortWittrock2012, author = {Rausch, Peter and Verpoort, Sven and Wittrock, Ulrich}, title = {Novel unimorph adaptive mirrors for astronomy applications}, series = {Proc. SPIE 8447, Adaptive Optics Systems III, 844764}, booktitle = {Proc. SPIE 8447, Adaptive Optics Systems III, 844764}, publisher = {SPIE}, doi = {10.25974/fhms-620}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:836-opus-6203}, year = {2012}, abstract = {We have developed a new type of unimorph deformable mirror for the correction of low-order Zernike modes. The mirror features a clear aperture of 50 mm combined with large peak-to-valley amplitudes of up to 35 μm. Newly developed fabrication processes allow the use of prefabricated, coated, super-polished glass substrates. The mirror's unique features suggest the use in several astronomical applications like the compensation of atmospheric aberrations seen by laser beacons, low light astronomy, and the use in woofer-tweeter systems. Additionally, the design enables an efficient correction of the inevitable wave-front error imposed by the floppy structure of primary mirrors in future large space 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.}, language = {en} } @inproceedings{RauschVerpoortWittrock2012, author = {Rausch, Peter and Verpoort, Sven and Wittrock, Ulrich}, title = {Characterization of a miniaturized unimorph deformable mirror for high power cw-solid state lasers}, series = {Proc. SPIE 8253, MEMS Adaptive Optics VI, 825309}, booktitle = {Proc. SPIE 8253, MEMS Adaptive Optics VI, 825309}, publisher = {SPIE}, doi = {10.25974/fhms-622}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:836-opus-6226}, year = {2012}, abstract = {We have developed a new type of unimorph deformable mirror for real-time intra-cavity phase control of high power cw-lasers. The approach is innovative in its combination of super-polished and pre-coated highly reflective substrates, the miniaturization of the unimorph principle, and the integration of a monolithic tip/tilt functionality. Despite the small optical aperture of only 9 mm diameter, the mirror is able to produce a stroke of several microns for low order Zernike modes, paired with a residual static root-mean-square aberration of less than 0.04 µm. In this paper, the characteristics of the mirror such as the influence functions, the dynamic behavior, and the power handling capability are reported. The mirror was subjected to a maximum of 490 W of laser-light at a wavelength of 1030 nm. Due to the high reflectivity of over 99.998 percent the mirror is able to withstand intensities up to 1.5 MW/cm2.}, language = {en} } @inproceedings{RauschVerpoortWittrock2014, author = {Rausch, Peter and Verpoort, Sven and Wittrock, Ulrich}, title = {Performance verification and environmental testing of a unimorph deformable mirror for space applications.}, series = {Proceedings of the 10th International Conference on Space Optics - ICSO, Tenerife, Spain}, booktitle = {Proceedings of the 10th International Conference on Space Optics - ICSO, Tenerife, Spain}, publisher = {FH M{\"u}nster}, doi = {10.25974/fhms-771}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:836-opus-7716}, year = {2014}, abstract = {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.}, language = {en} }