Shack-Hartmann wavefront sensor with high sensitivity by using long focal length microlens array

2011 ◽  
Author(s):  
Vinna Lin ◽  
Hsiang-Chun Wei ◽  
Guo-Dung J. Su
Keyword(s):  
Focal Length ◽  
High Sensitivity ◽  
Microlens Array ◽  
Wavefront Sensor

Focal length measurement of microlens array for Shack–Hartmann wavefront sensor using interferometer

2013 ◽  
Vol 52 (12) ◽  
pp. 124103 ◽  
Author(s):  
M. Senthil Kumar ◽  
C. S. Narayanamurthy ◽  
A. S. Kiran Kumar
Keyword(s):  
Focal Length ◽  
Microlens Array ◽  
Length Measurement ◽  
Wavefront Sensor

Defocus measuring the focal length of microlens array by grating prismatic interference

2010 ◽  
Author(s):  
Xianchang Zhu ◽  
Xuedong Cao ◽  
Shibin Wu ◽  
Fan Wu
Keyword(s):  
Focal Length ◽  
Microlens Array

scholarly journals Electrically Tunable-Focusing Liquid Crystal Microlens Array with Simple Electrode

Crystals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 431 ◽  
Author(s):  
Li-Lan Tian ◽  
Fan Chu ◽  
Hu Dou ◽  
Lei Li ◽  
Qiong-Hua Wang
Keyword(s):  
Liquid Crystal ◽  
Indium Tin Oxide ◽  
Focal Length ◽  
Microlens Array ◽  
Operating Voltage ◽  
Focusing Effect ◽  
Horizontal Orientation ◽  
Wide Range ◽  
Planar Electrodes ◽  
The Individual

An electrically tunable-focusing liquid crystal (LC) microlens array exhibiting a wide-range tunable focal length is proposed. The lower substrate has strip indium tin oxide (ITO) electrodes, the upper substrate has periodic ITO electrodes with a certain gap coated on the inner surface., and an LC microlens is generated between the two strip electrodes. For each LC microlens, the gap between the top planar electrodes is directly above the center of the microlens. Unlike the conventional LC lens, the individual LC microlens is not coated with ITO electrodes on the central part of its upper and lower substrates, which helps to maintain the LC’s horizontal orientation. In the voltage-off state, the focal length of the microlens array is infinity because of the homogeneous LC alignment. At a given operating voltage, an ideal gradient refractive index distribution is induced over the homogeneous LC layer, which leads to the focusing effect. The simulation result shows that the focal length of the LC microlens could be gradually drawn to 0.381 mm with a change of voltage.

scholarly journals Electrically-Tunable Blue Phase Liquid Crystal Microlens Array Based on a Photoconductive Film

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 65 ◽  
Author(s):  
Bing-Yau Huang ◽  
Shuan-Yu Huang ◽  
Chia-Hsien Chuang ◽  
Chie-Tong Kuo
Keyword(s):  
Refractive Index ◽  
Liquid Crystal ◽  
Electric Field ◽  
Uv Light ◽  
Focal Length ◽  
Incident Light ◽  
Microlens Array ◽  
Gradient Distribution ◽  
Phase Liquid ◽  
Blue Phase

This paper proposes an effective approach to fabricate a blue phase liquid crystal (BPLC) microlens array based on a photoconductive film. Owing to the characteristics of photo-induced conducting polymer polyvinylcarbazole (PVK), in which conductivity depends on the irradiation of UV light, a progressive mask resulting in the variation of conductivity is adopted to produce the gradient distribution of the electric field. The reorientations of liquid crystals according to the gradient distribution of the electric field induce the variation of the refractive index. Thus, the incident light experiences the gradient distribution of the refractive index and results in the focusing phenomenon. The study investigates the dependence of lens performance on UV exposure time, the focal length of the lens, and focusing intensities with various incident polarizations. The BPLC microlens array exhibits advantages such as electrically tunability, polarization independence, and fast response time.

scholarly journals The AOLI low-order non-linear curvature wavefront sensor: a method for high sensitivity wavefront reconstruction

2012 ◽  
Author(s):  
Jonathan Crass ◽  
Peter Aisher ◽  
Bruno Femenia ◽  
David L. King ◽  
Craig D. Mackay ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Wavefront Sensor ◽  
Wavefront Reconstruction ◽  
Non Linear ◽  
Low Order

An interferometric wavefront sensor for high-sensitivity low-amplitude measurements

2012 ◽  
Author(s):  
Nazim A. Bharmal ◽  
Richard M. Myers ◽  
Alastair G. Basden ◽  
Andrew P. Reeves
Keyword(s):  
High Sensitivity ◽  
Wavefront Sensor ◽  
Low Amplitude

scholarly journals High-Sensitivity X-ray Phase Imaging System Based on a Hartmann Wavefront Sensor

2021 ◽  
Vol 7 (1) ◽  
pp. 3
Author(s):  
Ginevra Begani Provinciali ◽  
Martin Piponnier ◽  
Laura Oudjedi ◽  
Xavier Levecq ◽  
Fabrice Harms ◽  
...  
Keyword(s):  
Imaging System ◽  
High Sensitivity ◽  
Test Sample ◽  
Wavefront Sensor ◽  
Reference Image ◽  
High Angular Resolution ◽  
Phase Imaging ◽  
X Ray ◽  
Laboratory Setup ◽  
The Impact

The Hartman wavefront sensor can be used for X-ray phase imaging with high angular resolution. The Hartmann sensor is able to retrieve both the phase and absorption from a single acquisition. The system calculates the shift in a series of apertures imaged with a detector with respect to their reference positions. In this article, the impact of the reference image on the final image quality is investigated using a laboratory setup. Deflection and absorption images of the same sample are compared using reference images acquired in air and in water. It can be easily coupled with tomographic setups to obtain 3D images of both phase and absorption. Tomographic images of a test sample are shown, where deflection images revealed details that were invisible in absorption. The findings reported in this paper can be used for the improvement of image reconstruction and for expanding the applications of X-ray phase imaging towards materials characterization and medical imaging.

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