Results 31 to 40 of about 1,567 (171)

Micro-machined membrane deformable mirrors for cryogenic adaptive optics [PDF]

, 2002
In this Thesis, the suitability of 37 actuator Micro-machined membrane deformable mirrors (MMDM) for adaptive optics at cryogenic temperatures is evaluated. A method is described to safely cool MMDMs to 78K. The initial surface figures of three MMDMs are
Dyson, H.M., Dyson, Harold Michael
core  

Liquid seal for compact micro-piston actuation at capillary tip

, 2020
Actuators at the tip of a sub-millimetric catheter could facilitatein vivointer-ventional procedures at cellular scales by enabling tissue biopsy, manipulationor supporting active micro-optics.
Power, Maura, Seichepine, Florent, Yang, Guang-Zhong, Barbot, Antoine   +3 more
core   +1 more source

Piston Dispersive Shock Wave Problem

, 2008
The piston shock problem is a classical result of shock wave theory. In this work, the analogous dispersive shock wave (DSW) problem for a fluid described by the nonlinear Schrödinger equation is analyzed. Asymptotic solutions are calculated for a piston
Hoefer, M A, M. A. Hoefer, M. J. Ablowitz, Ablowitz, M J, Engels, P, P. Engels   +5 more
core   +1 more source

Wavefront control simulations for the Giant Magellan Telescope: Field-dependent segment piston control [PDF]

, 2015
We present in this paper preliminary simulation results aimed at validating the GMT piston control strategy. Wewill in particular consider an observing mode in which an Adaptive Optics (AO) system is providing fast on-axisWF correction with the Adaptive ...
Bouchez, Antonin, Quiros-Pacheco, Fernando, Conan, Rod, Irarrazaval, Ben, McLeod, Brian   +4 more
core   +1 more source

Characterization of an Optical Transfer Function–based Phasing Technique for India’s Large Segmented Mirror Telescope

The Astronomical Journal
The upcoming 10 m class large Indian telescope is proposed to be built using segmented mirror technology. To achieve diffraction-limited image quality with a segmented mirror telescope, it is important to phase mirror segments with very high precision ...
Radhika Dharmadhikari, Padmakar Parihar
doaj   +1 more source

Multifunction reflector controlled by liquid piston for optical switch and beam steering

Optics Express, 2019
This paper presents a multifunction reflector controlled by liquid piston for optical switch and beam steering. The multifunction reflector consists of two liquid cavities that are designed with microchannels. Two holes covered with elastic membranes are fabricated on the upper surface of the liquid cavities.
Chao Liu, Di Wang, Lei Li, Qiong-Hua Wang   +3 more
openaire   +2 more sources

Keck Primary Mirror Closed-loop Segment Control Using a Vector-Zernike Wavefront Sensor

The Astrophysical Journal
We present the first on-sky segmented primary mirror closed-loop piston control using a Zernike wavefront sensor (ZWFS) installed on the Keck II telescope.
Maïssa Salama, Charlotte Guthery, Vincent Chambouleyron, Rebecca Jensen-Clem, J. Kent Wallace, Jacques-Robert Delorme, Mitchell Troy, Tobias Wenger, Daniel Echeverri, Luke Finnerty, Nemanja Jovanovic, Joshua Liberman, Ronald A. López, Dimitri Mawet, Evan C. Morris, Maaike van Kooten, Jason J. Wang, Peter Wizinowich, Yinzi Xin, Jerry Xuan   +19 more
doaj   +1 more source

Initial Design of an Optical-Access Piston Expansion Chamber for Wet-Expansion

Energy Procedia, 2017
Abstract High efficiency expanders which can cope with fluid-vapour mixtures (i.e wet expansion) at the inlet and during expansion have the potential to increase the power output from thermodynamic power cycles. Volumetric expanders are considered suitable, yet experimental results are scarce and there is no model that can predict the performance of ...
Lecompte, Steven, van den Broek, Martijn, De Paepe, Michel   +2 more
openaire   +1 more source

Lab tests of segment/petal phasing with a pyramid wavefront sensor and a holographic dispersed fringe sensor in turbulence with the Giant Magellan Telescope high contrast adaptive optics phasing testbed

, 2022
The Giant Magellan Telescope (GMT) design consists of seven circular 8.4-m diameter mirrors, together forming a single 25.4-m diameter primary mirror. This large aperture and collecting area can help extreme adaptive optics (ExAO) systems such as GMT's ...
Males, J.R., Demers, R., Sitarski, B.N., Bouchez, A.H., Long, J.D., Hedglen, A.D., Kautz, M., Van Gorkom, K., Lumbres, J., Rodack, A., Haffert, S.Y., Quirós-Pacheco, F., Close, L.M., Knight, J.M., Miller, K., Schatz, L., Guyon, O.   +16 more
core   +1 more source

Sparse aperture differential piston measurements using the pyramid wave-front sensor [PDF]

, 2016
In this paper we report on the laboratory experiment we settled in the Shanghai Astronomical Observatory (SHAO) to investigate the pyramid wave-front sensor (WFS) ability to measure the differential piston on a sparse aperture.
Chaoyan Wang, Chen, Xinyang, Nenghong Zhu, Wang, Chaoyan, Zhaojun Yan, Zhu, Liyun, Jianqing Cai, Tang, Zhenghong, Guido Agapito, Lixin Zheng, ARCIDIACONO, CARMELO, Zhenghong Tang, Yan, Zhaojun, Zheng, Lixin, Xinyang Chen, AGAPITO, GUIDO, Zhu, Nenghong, Carmelo Arcidiacono, Liyun Zhu, Cai, Jianqing   +19 more
core   +1 more source