Searched for: subject:"wavefront"
(1 - 20 of 34)

Pages

document
Kazasidis, O. (author)
Fast adaptive optics and comparatively slower active optics are cornerstones of modern-day astronomy. Such systems are installed on most current large ground-based observatories in the visible or infrared and are included in the design of all future observatories. Their role is twofold; first, to compensate for astronomical seeing, and second,...
doctoral thesis 2021
document
Fokkema, J.T. (author), van den Berg, Peter M. (author)
Maxwell's equations are transformed from a Cartesian geometry to a Riemannian geometry. A geodetic path in the Riemannian geometry is defined as the raypath on which the electromagnetic energy efficiently travels through the medium. Consistent with the spatial behavior of the Poynting vector, the metric tensor is required to be functionally...
journal article 2020
document
Piscaer, P.J. (author), Soloviev, O.A. (author), Verhaegen, M.H.G. (author)
This paper discusses various practical problems arising in the design and simulation of predictive control methods for adaptive optics. Although there has been increased attention towards optimal prediction and control methods for AO systems, they are often tested in simplified simulation environments. The use of advanced AO simulators...
conference paper 2020
document
Dwivedi, P. (author), Pereira, S.F. (author), Urbach, Paul (author)
Wavefront aberration measurements are required to test an extreme ultraviolet (EUV) imaging system. For a high-NA EUV imaging system, where conventional wavefront-sensing techniques show limitations, ptychography can be used for this purpose. However, at the wavelength region of EUV (i.e., 13.5 nm), the position accuracy of the scanning mask...
journal article 2019
document
Haji Heidari Varnosfaderani, Mehdi (author), Mozaffarzadeh, M. (author), Upputuri, Paul Kumar (author), Pramanik, Manojit (author)
Traditional optical devices rely on light propagation along a straight path. However, when the light propagates through a blurred medium, its direction get scattered by microscopic particles. This inhomogeneous distortion results in a diffused focus point. Light scattering is one of the main limitations for the optical imaging. This...
conference paper 2019
document
Chiu, P. (author), Vonmetz, Kurt (author), Canini, Federico (author), Urbach, Paul (author)
Cubic phase wavefront coding technique is applied to an imaging system with the aim of extending the depth of field (DOF). The design is based on the wavefront coding method proposed by Dowski and Cathey<sup>1</sup>. The method employs a cubic phase mask (CPM) to modify the point spread function (PSF) of the imaging system under incoherent...
conference paper 2019
document
Brunner, A.E. (author)
In the coming decade, a new generation of extremely large-scale ground-based astronomical telescopes will see first light. It is well known that increasing the size of the telescope aperture is only beneficial if the adaptive optics (AO) system, which compensates for turbulence-induced wavefront aberrations, scales accordingly. For the extreme...
doctoral thesis 2018
document
Wilding, D. (author), Pozzi, P. (author), Soloviev, O.A. (author), Vdovin, Gleb (author), Verhaegen, M.H.G. (author)
In life sciences, interest in the microscopic imaging of increasingly complex three dimensional samples, such as cell spheroids, zebrafish embryos, and in vivo applications in small animals, is growing quickly. Due to the increasing complexity of samples, more and more life scientists are considering the implementation of adaptive optics in...
conference paper 2018
document
Verstraete, H.R.G.W. (author)
Optical coherence tomography (OCT) is a technique for non-invasive imaging based on low coherence interferometry. Its main application is found in ophthalmology, where it is used for 3D in vivo imaging of the cornea and the retina. OCT has evolved over the past decade as one of the most important ancillary tests in ophthalmic practice, providing...
doctoral thesis 2017
document
Mocci, J. (author), Cua, M. (author), Lee, S. (author), Jian, Y (author), Pozzi, P. (author), Quintavalla, M. (author), Trestino, C. (author), Verstraete, H.R.G.W. (author), Wahl, D. (author), Muradore, R. (author), Zawadzki, R.J. (author), Verhaegen, M.H.G. (author), Sarunic, M.V. (author), Bonora, S. (author)
The use of adaptive lenses instead of deformable mirrors can simplify the implementation of an adaptive optics system. The recently introduced Multi-actuator Adaptive Lens (MAL) can be used in closed loop with a wavefront sensor to correct for time-variant wavefront aberrations. The MAL can guarantee a level of correction and a response time...
conference paper 2017
document
Gong, H. (author), Soloviev, O.A. (author), Verhaegen, M.H.G. (author), Vdovin, Gleb (author)
We present a quantitative phase imaging microscope based on a Shack-Hartmann sensor, that directly reconstructs the optical path difference (OPD) in reflective mode. Comparing with the holographic or interferometric methods, the SH technique needs no reference beam in the setup, which simplifies the system. With a preregistered reference, the...
journal article 2017
document
Agbana, T.E. (author), Yang, H. (author), Soloviev, O.A. (author), Vdovin, Gleb (author), Verhaegen, M.H.G. (author)
This paper presents experimental results of a static aberration control algorithm based on the linear relation be- tween mean square of the aberration gradient and the second moment of point spread function for the generation of control signal input for a deformable mirror (DM). Results presented in the work of Yang et al.1 suggested a good...
conference paper 2016
document
Pozzi, P. (author), Wilding, D. (author), Soloviev, O.A. (author), Vdovin, Gleb (author), Verhaegen, M.H.G. (author)
This proceeding reports early results in the development of a new technique for adaptive optics in confocal microscopy. The term adaptive optics refers to the branch of optics in which an active element in the optical system is used to correct inhomogeneities in the media through which light propagates. In its most classical form, mostly used in...
conference paper 2016
document
Yoo, H.W. (author)
Confocal laser scanning microscopy (CLSM) is considered as one of the major advancements in microscopy in the last century and is widely accepted as a 3D fluorescence imaging tool for biological studies. For the emerging biological questions CLSM requires fast imaging to detect rapid biological processes and aberration-corrected imaging to...
doctoral thesis 2015
document
Agbana, T.E. (author), Soloviev, O. (author), Bezzubik, V. (author), Patlan, V. (author), Verhaegen, M. (author), Vdovin, G.V. (author)
We have implemented an extended depth of field optical system by wavefront coding with a micromachined membrane deformable mirror. This approach provides a versatile extension to standard wavefront coding based on fixed phase mask. First experimental results validate the feasibility of the use of adaptive optics for variable depth wavefront...
conference paper 2015
document
Shakeri, S.M. (author), Hulsken, B. (author), Van Vliet, L.J. (author), Stallinga, S. (author)
Whole Slide Imaging (WSI) systems are used in the emerging field of digital pathology for capturing high-resolution images of tissue slides at high throughput. We present a technique to measure the optical aberrations of WSI systems using a Shack-Hartmann wavefront sensor as a function of field position. The resulting full-field aberration maps...
conference paper 2015
document
Gong, H. (author), Pozzi, P. (author), Soloviev, O.A. (author), Verhaegen, M.H.G. (author), Vdovine, G.V. (author)
We investigate the possibility of interferometric optical field sensor with DMD forming a series of sampling interferometers in the pupil of an optical system. Our preliminary experiment validates the feasibility of our approach for the field reconstruction in the case of coherent field. We believe that this approach can be extended to sensing...
conference paper 2015
document
Polo, A. (author)
In the semiconductor industry, optical lithography is presently the most widespread technology used to print a geometrical pattern on a semiconductor wafer. Because of the plans imposed by the International Technology Roadmap for Semiconductors (ITRS) for more powerful and smaller chips, new printing technologies capable of printing smaller...
doctoral thesis 2014
document
Konijnenberg, A.P. (author), Wei, L. (author), Kumar, N. (author), Couto Correa Pinto Filho, L. (author), Cisotto, L. (author), Pereira, S.F. (author), Urbach, H.P. (author)
In several optical systems, a specific Point Spread Function (PSF) needs to be generated. This can be achieved by shaping the complex field at the pupil. The Extended Nijboer-Zernike (ENZ) theory relates complex Zernike modes on the pupil directly to functions in the focal region. In this paper, we introduce a method to engineer a PSF using the...
journal article 2014
document
Cui, M. (author), Hovenier, J.N. (author), Ren, Y. (author), Vercruyssen, N. (author), Gao, J.R. (author), Kao, T.Y. (author), Hu, Q. (author), Reno, J.L. (author)
We report on both measurements and simulations of the beam profile and wavefront of a single-mode, 3.5?THz quantum cascade wire laser, incorporating a lateral corrugated metal-metal waveguide, 3rd-order distributed feedback grating. The intrinsic wavefront was measured by using a Hartmann wavefront sensor (HWS) without any optical components...
journal article 2013
Searched for: subject:"wavefront"
(1 - 20 of 34)

Pages