Actuation profiles to form Zernike shapes with a thermal active mirror

Saathof, Rudolf; Schutten, Gerrit Jan M.; Spronck, Jo W.; Schmidt, Robert H.

doi:10.1364/ol.40.000205

Cited by 17 publications

(6 citation statements)

References 11 publications

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“…The two mirrors could be realized as adaptive optics lowering the round-trip loss and improving mode matching between the fundamental eigenmode of the cavity and the squeezed light or output field of the interferometer. First experiments on high-resolution adaptive optics based on thermally induced deformations using heater arrays in thermal contact with the optics [105], or by projecting images onto optics [141], have demonstrated the soundness of this approach. How much active technology can help to lower round-trip loss in filter cavities is unclear though.…”

Section: Active Optics Technologymentioning

confidence: 99%

Squeezed vacuum states of light for gravitational wave detectors

2018

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A century after Einstein's formulation of General Relativity, the detectors of the Laser Interferometer Gravitational-wave Observatory (LIGO) made the first direct detection of gravitational waves. This historic achievement was the culmination of a world-wide effort and decades of instrument research. While sufficient for this monumental discovery, the current generation of gravitational-wave detectors represent the least sensitive devices necessary for the task; improved detectors will be required to fully exploit this new window on the Universe. In this paper, we review the application of squeezed vacuum states of light to gravitational-wave detectors as a way to reduce quantum noise, which currently limits their performance in much of the detection band.

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Section: Active Optics Technologymentioning

confidence: 99%

Squeezed vacuum states of light for gravitational wave detectors

2018

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“…Lück et al achieved an almost ×38 decrease in the level of wave-front distortion. A somewhat similar approach was followed by Saathof et al [158,159], in which the correction was introduced by a deformable mirror, but thermally actuated by illumination with a predefined distributed light. This heating light was provided and formed using a video projector and the mirror placed between the reflective layer and the substrate, was covered with an absorptive layer that was heated by the light provided by the projector.…”

Section: Thermal Lens Studies Related To High-power Lasers and Solid To Materialsmentioning

confidence: 99%

Thermal lensing: outside of the lasing medium

Dobek

2022

Appl. Phys. B

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The thermal lens formed in a thermo-optical material as a result of its inhomogeneous heating, is a well-known phenomenon that has found widespread interest in the last decades, especially in the field of laser engineering and photo-thermal spectroscopy. In recent years, growing interest in the application of thermal lensing in different fields of optics and material studies has been observed. This review summarizes the latest efforts made by the scientific community to develop ways of using the phenomenon of thermal lensing. Its applications in spectroscopy, in laser beam formation and in imaging are described. The advantages and disadvantages of the thermal lensing in regard to these areas along with the potential future applications of the phenomenon are discussed.

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“…The control objective is to keep the temperature distribution constant using the feedback information provided by the sensors. Similar control problems appear in various real-life applications, such as for example in control of thermally actuated deformable mirrors used in adaptive optics applications [55,56,57,58,59]. The temperature dynamics is governed by the 2D heat equation with constant parameters.…”

Section: Control Problem Formulationmentioning

confidence: 99%

Sparsity preserving optimal control of discretized PDE systems

Haber

Verhaegen

2018

Computer Methods in Applied Mechanics and Engineering

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We focus on the problem of optimal control of large-scale systems whose models are obtained by discretization of partial differential equations using the Finite Element (FE) or Finite Difference (FD) methods. The motivation for studying this pressing problem originates from the fact that the classical numerical tools used to solve low-dimensional optimal control problems are computationally infeasible for large-scale systems. Furthermore, although the matrices of large-scale FE or FD models are usually sparse banded or highly structured, the optimal control solution computed using the classical methods is dense and unstructured. Consequently, it is not suitable for efficient centralized and distributed real-time implementations. We show that the a priori (sparsity) patterns of the exact solutions of the generalized Lyapunov equations for FE and FD models are banded matrices. The a priori pattern predicts the dominant non-zero entries of the exact solution. We furthermore show that for wellconditioned problems, the a priori patterns are not only banded but also sparse matrices. On the basis of these results, we develop two computationally efficient methods for computing sparse approximate solutions of generalized Lyapunov equations. Using these two methods and the inexact Newton method, we show that the solution of the generalized Riccati equation can be approximated by a banded matrix. This enables us to develop a novel computationally efficient optimal control approach that is able to preserve the sparsity of the control law. We perform extensive numerical experiments that demonstrate the effectiveness of our approach.

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Actuation profiles to form Zernike shapes with a thermal active mirror

Cited by 17 publications

References 11 publications

Squeezed vacuum states of light for gravitational wave detectors

Squeezed vacuum states of light for gravitational wave detectors

Thermal lensing: outside of the lasing medium

Sparsity preserving optimal control of discretized PDE systems

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