TY  - JOUR
A1  - Wittrock, Ulrich
T1  - Laryngeally echolocating bats (Brief Communication Arising)
JF  - Nature
Y1  - 2010
U6  - http://dx.doi.org/10.1038/nature09156
VL  - 466
SP  - E6
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  - JOUR
A1  - Verpoort, Sven
A1  - Wittrock, Ulrich
T1  - Actuator patterns for unimorph and bimorph deformable mirrors
JF  - Appl. Opt.
N2  - 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.
Y1  - 2010
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:836-opus-6490
UR  - http://www.opticsinfobase.org
VL  - 49
SP  - G37
EP  - G46
PB  - OSA
ER  -