Download or read book Higher Order Wavefront Correction and Axial Scanning in a Single Fast and Compact Piezo driven Adaptive Lens written by Hitesch Gowda and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: We present a compact adaptive glass membrane lens for higher order wavefront correction and axial scanning, driven by integrated segmented piezoelectric actuators. The membrane can be deformed in a combination of rotational symmetry providing focus control of up to ± 6 m−1 and spherical aberration correction of up to 5 wavelengths and different discrete symmetries to correct higher order aberrations such as astigmatism, coma and trefoil by up to 10 wavelengths. Our design provides a large clear aperture of 12 mm at an outer diameter of the actuator of 18 mm, a thickness of 2 mm and a response time of less than 2 ms

Download or read book Investigation of Aberration Correction and Axial Scanning in Microscopy Employing Adaptive Lenses written by Katrin Philipp and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Diffraction limited Axial Scanning in Thick Biological Tissue with an Aberration correcting Adaptive Lens written by Katrin Philipp and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Wavefront Correction for Two photon Microscopy Using a Nematic Liquid Crystal Spatial Light Modulator written by Gunnsteinn Hall and published by . This book was released on 2009 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Adaptive Optics written by Edgar Moreno Vuelban and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Adaptive Optic for Correcting Low order Wavefront Aberrations written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Adaptive Optics used for correcting low-order wavefront aberrations were tested and compared using interferometry, beam propagation, and a far-field test. Results confirm that the design and manufacturing specifications were met. Experimental data also confirms theoretical performance expectations, indicating the usefulness of these optics (especially in a laser-beam processing system), and identifying the resulting differences between the two fabrication methods used to make the optics.

Download or read book Wavefront Sensorless Adaptive Optics Swept Source Optical Coherence Tomography at 1060nm written by Sujin Tom Lee and published by . This book was released on 2015 with total page 49 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical Coherence Tomography (OCT) has revolutionized modern ophthalmology, providing depth resolved images of the retinal layers in a system that is suited to a clinical environment. A limitation on the performance and utilization of the OCT systems has been the lateral resolution; whereas the axial resolution is a function of the light source, the lateral resolution is dependent on the delivery optics. In this thesis, a compact lens based OCT system is presented that is capable of imaging the different retinal layers at a cellular lateral resolution with the combination of wavefront sensorless adaptive optics with dual variable optical elements. The central operating imaging wavelength of the wavelength swept OCT engine was 1060nm, close to the dispersion minimum of water (and the vitreous humor in the eye). A commercially available variable focal length lens is utilized to correct for a wide range of defocus commonly found in patient's eyes, and a multi-actuator deformable lens for aberration correction to obtain near diffraction limited imaging at the retina. A parallel processing computational platform permitted real-time image acquisition and display. Cross-sectional images of the retinal layers and en face images of the cone photoreceptor mosaic acquired in vivo from research subjects are presented.

Download or read book A CCD Based Curvature Wavefront Sensor for Adaptive Optics in Astronomy written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Adaptive Optics (AO) is a technique for compensating the distortions introduced by atmospheric turbulence in astronomical imaging. To measure the distortions a wavefront sensor is needed. There are a number of fundamentally different types of wavefront sensors, one of which is the curvature wavefront sensor. At the European Southern Observatory (ESO) in Garching, Germany, several adaptive optics systems using curvature wavefront sensors are being developed for the Very Large Telescope (VLT) and the VLT interferometer (VLTI). Curvature AO-systems have traditionally used avalanche photodiodes (APDs) as detectors due to strict requirements of very short integration times (200 microsec) and very low readout noise. Advances in charge-coupled device (CCD) technology motivated an investigation of the use of a specially designed CCD as the wavefront sensor detector in a 60-element curvature AO system. A CCD has never been used before as the wavefront sensor in a low light level curvature adaptive optics system. This thesis shows that a CCD can achieve nearly the same performance as APDs at a fraction of the cost and with reduced complexity for high order wavefront correction. Moreover the CCD has higher quantum efficiency and a greater dynamic range than APDs. A readout noise of less than 1.5 electrons at 4000 frames per second was achieved. A back-illuminated thinned version of this CCD can replace APDs as the best detector for high order curvature wavefront sensing. This thesis presents the concept, the design and the evaluation of the CCD. The first frontside devices were successfully evaluated and the performance of the detector was proven in a laboratory experiment.

Download or read book Robust and Compact Piezo Actuated Lenses with Dynamic Aberration Correction written by Hitesh Gowda Bettaswamy Gowda and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fast Wavefront Reconstruction in Large Adaptive Optics Systems Using the Fourier Transform written by and published by . This book was released on 2002 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wavefront Reconstruction using the Fast Fourier Transform and spatial filtering is shown to be computationally tractable and sufficiently accurate for use in large Shack Hartmann-based adaptive optics systems (up to at least 10,000 actuators). This method is significantly faster and can have lower noise propagation than traditional VMM reconstructors. The boundary problem which prevented the accurate reconstruction of phase in circular apertures using square-grid FTs is identified and solved. The methods are adapted for use on the Fried-geometry. Detailed performance analysis of mean squared error and noise propagation for FT methods is presented, using both theory and simulation.

Download or read book Generalized Alvarez Lens for Correction of Laser Aberrations written by K. N. LaFortune and published by . This book was released on 2004 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Alvarez lens (US Patent No. 3,305,294 [1]) is a compact aberration corrector. The original design emphasized in the patent consists of a pair of adjacent optical elements that provide a variable focus. A lens system with a variable effective focal length is nothing new. Such systems are widely used in cameras, for example. It is the compactness and simplicity of operation that is the key advantage of the Alvarez lens. All of the complexity is folded into the design and fabrication of the optical elements. As mentioned in the Alvarez patent [1] and elaborated upon in Palusinski et al. [2], if one is willing to fold even more complexity into the optical elements, it is possible to correct higher-order aberrations as well. There is no theoretical limit to the number or degree of wavefront distortions that can be corrected. The only limitation is that there must be a fixed relative magnitude of the aberrations. Independent correction of each component of the higher-order aberrations can not be performed without additional elements and degrees of freedom [3]. Under some circumstances, coupling may be observed between different aberrations. This can be mitigated with the appropriate choice of design parameters. New methods are available today that increase the practicality of making higher-order aberration correctors [4,5,6].

Download or read book Adaptive Optics Correction in Real Time for Dynamic Wavefront Errors written by Jiang Wenhan and published by . This book was released on 1990 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper reports on the principles for the use of, and the experimental results obtained from, an adaptive optics system for correcting dynamic wavefront errors in real time. The system consists of a 21-element deformable mirror, a lateral shearing interferometer, and a parallel electronic control system. Keywords: Adaptive optics; Wavefront sensing; Deformable mirror; Chinese translations. (jhd).

Download or read book Novel Adaptive Optics Concepts written by Stephan Kellner and published by . This book was released on 2005 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Direct Wavefront Sensing for Adaptive Optics written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Handbook of Biomedical Optics written by David A. Boas and published by CRC Press. This book was released on 2016-04-19 with total page 816 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biomedical optics holds tremendous promise to deliver effective, safe, non- or minimally invasive diagnostics and targeted, customizable therapeutics. Handbook of Biomedical Optics provides an in-depth treatment of the field, including coverage of applications for biomedical research, diagnosis, and therapy. It introduces the theory and fundamental

Download or read book Adaptive Optics for Industry and Medicine written by Christopher Dainty and published by Imperial College Press. This book was released on 2008 with total page 519 pages. Available in PDF, EPUB and Kindle. Book excerpt: This proceedings volume presents the very latest developments in non-astronomical adaptive optics. This international workshop, the sixth in a biennial series, was the largest ever held and boasted significant involvement by industry. Adaptive optics is on the verge of being used in many products; indeed, at this meeting, the use of adaptive optics in DVD players was disclosed for the first time. Sample Chapter(s). Liquid Crystal Lenses For Correction Of Presbyopia (586 KB). Contents: Wavefront Correctors and Control: Liquid Crystal Lenses for Correction of Presbyopia (G Li & N Peyghambarian); Woofer-Tweeter Adaptive Optics (T Farrell & C Dainty); Wavefront Sensors: A Fundamental Limit for Wavefront Sensing (C Paterson); Direct Diffractive Image Simulation (A P Maryasov et al.); Adaptive Optics in Vision Science: A Study of Field Aberrations in the Human Eye (A V Goncharov et al.); Characterization of an AO-OCT System (J W Evans et al.); Adaptive Optics in Optical Storage and Microscopy: Commercialization of the Adaptive Scanning Optical Microscope (ASOM) (B Potsaid et al.); Towards Four Dimensional Particle Tracking for Biological Applications (H I Campbell et al.); Adaptive Optics in Lasers: New Results in High Power Lasers Beam Correction (A Kudryashov et al.); Adaptive Optics Control of Solid-State Lasers (W Lubeigt et al.); Adaptive Optics in Communication and Atmospheric Compensation: Fourier Image Sharpness Sensor for Laser Communications (K N Walker & R K Tyson); Adaptive Optics System for a Small Telescope (G Vdovin et al.); and other papers. Readership: Industry- and university-level researchers in optics and laser physics.

Download or read book High Resolution Imaging in Microscopy and Ophthalmology written by Josef F. Bille and published by Springer. This book was released on 2019-08-13 with total page 407 pages. Available in PDF, EPUB and Kindle. Book excerpt: This open access book provides a comprehensive overview of the application of the newest laser and microscope/ophthalmoscope technology in the field of high resolution imaging in microscopy and ophthalmology. Starting by describing High-Resolution 3D Light Microscopy with STED and RESOLFT, the book goes on to cover retinal and anterior segment imaging and image-guided treatment and also discusses the development of adaptive optics in vision science and ophthalmology. Using an interdisciplinary approach, the reader will learn about the latest developments and most up to date technology in the field and how these translate to a medical setting. High Resolution Imaging in Microscopy and Ophthalmology – New Frontiers in Biomedical Optics has been written by leading experts in the field and offers insights on engineering, biology, and medicine, thus being a valuable addition for scientists, engineers, and clinicians with technical and medical interest who would like to understand the equipment, the applications and the medical/biological background. Lastly, this book is dedicated to the memory of Dr. Gerhard Zinser, co-founder of Heidelberg Engineering GmbH, a scientist, a husband, a brother, a colleague, and a friend.