Application of Shack-Hartmann wavefront sensor for testing optical systems

2007 ◽  
Author(s):  
Jiri Novak ◽  
Pavel Novak ◽  
Antonin Miks
Keyword(s):  
Optical Systems ◽  
Wavefront Sensor

scholarly journals Lorentz Force Actuated Tunable-Focus Liquid Lens

Micromachines ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 714
Author(s):  
Kari L. Van Grinsven ◽  
Alireza Ousati Ashtiani ◽  
Hongrui Jiang
Keyword(s):  
Lorentz Force ◽  
Large Range ◽  
Focal Length ◽  
Optical Systems ◽  
Wavefront Sensor ◽  
Physical Movement ◽  
Liquid Lenses ◽  
Liquid Lens ◽  
Magnetically Actuated

Tunable-focus liquid lenses provide focal length tuning for optical systems, e.g., cameras, where physical movement of rigid lenses are not an option or not preferable. In this work we present a magnetically actuated liquid lens utilizing the Lorentz force to vary the focal length as the current through the system is varied. The resulting lens can operate as both a diverging and a converging lens depending on the direction of current applied and has a large range of focal lengths, from −305 mm to –111 mm and from 272 mm to 146 mm. We also characterized the aberrations of the lens during the actuation with a Shack–Hartmann wavefront sensor, and utilized the lens for imaging, during which we measured a resolution of 7.13 lp/mm.

scholarly journals Wavefront Sensing for Evaluation of Extreme Ultraviolet Microscopy

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6426
Author(s):  
Mabel Ruiz-Lopez ◽  
Masoud Mehrjoo ◽  
Barbara Keitel ◽  
Elke Plönjes ◽  
Domenico Alj ◽  
...  
Keyword(s):  
Extreme Ultraviolet ◽  
Numerical Aperture ◽  
Laser Flash ◽  
Optical Systems ◽  
Wavefront Sensor ◽  
Reliable Technique ◽  
Phase Measurements ◽  
X Ray ◽  
Classical Calculation

Wavefront analysis is a fast and reliable technique for the alignment and characterization of optics in the visible, but also in the extreme ultraviolet (EUV) and X-ray regions. However, the technique poses a number of challenges when used for optical systems with numerical apertures (NA) > 0.1. A high-numerical-aperture Hartmann wavefront sensor was employed at the free electron laser FLASH for the characterization of a Schwarzschild objective. These are widely used in EUV to achieve very small foci, particularly for photolithography. For this purpose, Schwarzschild objectives require highly precise alignment. The phase measurements acquired with the wavefront sensor were analyzed employing two different methods, namely, the classical calculation of centroid positions and Fourier demodulation. Results from both approaches agree in terms of wavefront maps with negligible degree of discrepancy.

scholarly journals Testing and characterization of challenging optics and optical systems with Shack Hartmann wavefront sensors

2019 ◽  
Vol 215 ◽  
pp. 06003
Author(s):  
Julie Siv ◽  
Rafael Mayer ◽  
Guillaume Beaugrand ◽  
Guillaume Tison ◽  
Rémy Juvénal ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Optical System ◽  
Optical Sensors ◽  
Optical Filters ◽  
Optical Characterization ◽  
Optical Systems ◽  
Wavefront Sensor ◽  
Smart Vehicles ◽  
Manufacturing Techniques

The Shack-Hartman wavefront sensor is a common metrology tool in the field of laser, adaptive optics and astronomy. However, this technique is still scarcely used in optics and optical system metrology. With the development of manufacturing techniques and the increasing need for optical characterization in the industry, the Shack-Hartmann wavefront sensor emerges as an efficient complementary tool to the well-established Fizeau interferometry for optical system metrology. Moreover, the raise of smart vehicles equipped with optical sensors and augmented reality, the optical characterization of glass and transparent flat materials becomes an issue that can be addressed with Shack-Hartmann sensors. Aberration measurements of challenging optics will be presented such as optical filters, thin flat optics, aspheric lenses and large optical assemblies.

scholarly journals Accuracy of Shack–Hartmann wavefront sensor using a coherent wound fibre image bundle

2018 ◽  
Vol 35 ◽  
Author(s):  
Jessica R. Zheng ◽  
Michael Goodwin ◽  
Jon Lawrence
Keyword(s):  
Measurement Accuracy ◽  
Signal To Noise Ratio ◽  
Optical Systems ◽  
Wavefront Sensor ◽  
Estimation Accuracy ◽  
Signal To Noise ◽  
Centroid Method ◽  
Structure Defects ◽  
Noise Ratio ◽  
Bundle Structure

AbstractShack–Hartmannwavefront sensors using wound fibre image bundles are desired for multi-object adaptive optical systems to provide large multiplex positioned by Starbugs. The use of a large-sized wound fibre image bundle provides the flexibility to use more sub-apertures wavefront sensor for ELTs. These compact wavefront sensors take advantage of large focal surfaces such as the Giant Magellan Telescope. The focus of this paper is to study the wound fibre image bundle structure defects effect on the centroid measurement accuracy of a Shack–Hartmann wavefront sensor. We use the first moment centroid method to estimate the centroid of a focused Gaussian beam sampled by a simulated bundle. Spot estimation accuracy with wound fibre image bundle and its structure impact on wavefront measurement accuracy statistics are addressed. Our results show that when the measurement signal-to-noise ratio is high, the centroid measurement accuracy is dominated by the wound fibre image bundle structure, e.g. tile angle and gap spacing. For the measurement with low signal-to-noise ratio, its accuracy is influenced by the read noise of the detector instead of the wound fibre image bundle structure defects. We demonstrate this both with simulation and experimentally. We provide a statistical model of the centroid and wavefront error of a wound fibre image bundle found through experiment.

Joint processing of image plane and wavefront sensor information to measure large aberrations in optical systems

1998 ◽  
Author(s):  
Michael C. Roggemann ◽  
Timothy J. Schulz ◽  
Byron M. Welsh ◽  
Chee Wai Ngai ◽  
Jason T. Kraft
Keyword(s):  
Image Plane ◽  
Optical Systems ◽  
Wavefront Sensor ◽  
Joint Processing ◽  
Sensor Information

Atomic Resolution in Crystal Aperture Stem

1990 ◽  
Vol 48 (1) ◽  
pp. 236-237
Author(s):  
J T Fourie
Keyword(s):  
Optical System ◽  
Spherical Aberration ◽  
Three Dimensional ◽  
Transmission Function ◽  
Optical Systems ◽  
Bragg Angle ◽  
Electron Optical System ◽  
Intimate Contact ◽  
Diffraction Effects ◽  
Design Aspect

The attempts at improvement of electron optical systems to date, have largely been directed towards the design aspect of magnetic lenses and towards the establishment of ideal lens combinations. In the present work the emphasis has been placed on the utilization of a unique three-dimensional crystal objective aperture within a standard electron optical system with the aim to reduce the spherical aberration without introducing diffraction effects. A brief summary of this work together with a description of results obtained recently, will be given.The concept of utilizing a crystal as aperture in an electron optical system was introduced by Fourie who employed a {111} crystal foil as a collector aperture, by mounting the sample directly on top of the foil and in intimate contact with the foil. In the present work the sample was mounted on the bottom of the foil so that the crystal would function as an objective or probe forming aperture. The transmission function of such a crystal aperture depends on the thickness, t, and the orientation of the foil. The expression for calculating the transmission function was derived by Hashimoto, Howie and Whelan on the basis of the electron equivalent of the Borrmann anomalous absorption effect in crystals. In Fig. 1 the functions for a g220 diffraction vector and t = 0.53 and 1.0 μm are shown. Here n= Θ‒ΘB, where Θ is the angle between the incident ray and the (hkl) planes, and ΘB is the Bragg angle.

SPATIAL AND TEMPORAL INSTABILITIES IN PASSIVE OPTICAL SYSTEMS

1988 ◽  
Vol 49 (C2) ◽  
pp. C2-343-C2-348
Author(s):  
L. A. LUGIATO ◽  
C. OLDANO ◽  
Kaige WANG ◽  
L. SANTIRANA ◽  
L. M. NARDUCCI ◽  
...  
Keyword(s):  
Optical Systems
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