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Irregular surfaces - measurements and ZEMAX simulations
Melich, Radek ; Psota, Pavel ; Lédl, Vít ; Václavík, Jan
Surfaces produced on optical elements are loaded by dierent kinds of irregularities whose allowable amplitudes are prescribed by optical tolerances defined by an optical designer. An important feedback between realized and designed surfaces can be achieved using interferometry or profilometry measurements for instance. This article discusses dierent kinds of representation and visualization of those measurements in ZEMAX, enabling optical designer to evaluate an impact of the irregular surface on the optical system performance.
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Optimization of electrode geometry and piezoelectric layer thickness of a deformable mirror
Kruchenko, Alexey ; Nováková, Kateřina ; Mokrý, Pavel
Deformable mirrors are the most commonly used wavefront correctors in adaptive optics systems. Nowadays, many applications of adaptive optics to astronomical telescopes, high power laser systems, and similar fast response optical devices require large diameter deformable mirrors with a fast response time and high actuator stroke. In order to satisfy such requirements, deformable mirrors based on piezoelectric layer composite structures have become a subject of intense scientific research during last two decades. In this paper, we present an optimization of several geometric parameters of a deformable mirror that consists of a nickel reflective layer deposited on top of a thin lead zirconate titanate (PZT) piezoelectric disk. Honeycomb structure of gold electrodes is deposited on the bottom of the PZT layer. The analysis of the optimal thickness ratio between the PZT and nickel layers is performed to get the maximum actuator stroke using the finite element method. The effect
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Measurement of Vibration Mode Structure for Adaptive Vibration Suppression System by Digital Holography
Psota, Pavel ; Lédl, Vít ; Doleček, Roman ; Mokrý, P. ; Kopecký, V.
Previously the frequency-shifted digital holographic interferometry (FSDHI) for measurement of vibration amplitudes in range of nanometers was introduced and verified by authors [1,2]. The method FSDHI addressed some of the drawbacks of the conventional methods and was used mainly for piezoelectric transformer vibration amplitudes and mode structures measurement [3]. The limiting factor for application of this method is the maximal measured value of the vibration amplitude without the risk of ambiguity. The value is approximately 80nm for the frequency doubled Nd: YAG line. Since FSDHI enables us to precisely measure vibration amplitudes over the whole inspected area with very high lateral resolution, it could also be a very useful tool for measurement of vibration amplitudes and mode structures for research in the field of adaptive suppression systems. Such a measurement would provide a necessary feedback about the system behavior.This was the reason why we put an effort
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Planar acoustic metamaterials with the active control of acoustic impedance using a piezoelectric composite actuator
Nováková, Kateřina ; Mokrý, P. ; Václavík, J. ; Marton, P. ; Cernik, M. ; Psota, Pavel ; Doleček, Roman ; Lédl, Vít
In the Paper, there are presented methods for a precise active control of the acoustic impedance of large planar structures, e.g glass plates or shells, by means of distributed flexible piezoelectric composite actuators which are connected to passive or active electronic shunt circuits. Design of tunable acoustic metamaterials is realized using Finite Element Method simulations and their acoustic properties are evaluated using acoustic transmission loss measurements. Static and dynamic displacements of the metamaterials produced by electric voltage are measured using Digital Holographic Interferometry. We believe that deep understanding of presented systems should result in future applications that improve the quality of everyday life.
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Possibilities of welding observation with regard of sielding gas
Rohan, P. ; Vojtíšek, Petr
MAG welding is characterized by very rapid processes in extreme condition of electric arc. To describe welding is necessary to use sufficiently quick equipment. Especially in the transition region between dip and spray transfer the processes develop quickly. Characterization of transition area in active three component shielding gas was carried out visually by hi speed camera equipment and electrically by quick response electronic measurement system.
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Chromatic Aberration of Several Important Refractors of the 19th and 20th Century
Rail, Zdeněk ; Jareš, Daniel ; Tomka, David ; Doleček, Roman
In 19th century refractors dominated in astronomical research. Lenses of these devices were made of the classical glasses. Main optical aberration of these telescopes was residual chromatism. In this paper residual chromatism of several important refractors is shown. We managed to get optical parameters of 40, 36, 25 inch refractors of Alvan Clark, 12 inch telescope of Greenwiche observatory and 6 inch heliometer of Joseph Fraunhofer with which paralax of star was measured for the first time. The paper contains parameters of the dublet of König telescope of Prague‘s observatory
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Optical Designs of the Chromospheric Telescope and the Coronograph
Rail, Zdeněk ; Jareš, Daniel ; Tomka, David ; Doleček, Roman
This paper presents optical designs of several devices which are used in solar astronomy – coronograph and telescope for the observations of chromosphere. We insist on high quality of images and simplicity of the whole optical design. The coronograph is composed of 7 optical parts to minimize dispersed light. The chromospheric telescope is designed both for birefringent and Fabry-Perot filters. All these designs could be used as the initial solutions for much complicated devices
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