On-chip monolithic wide-angle field-of-view metalens based on quadratic phase profile

Metasurfaces, being composed of subwavelength nanostructures, can achieve peculiar optical manipulations of phase, amplitude, etc. A large field of view (FOV) is always one of the most desirable characteristics of optical systems. In this study, metasurface-based quadratic reflectors (i.e., meta-reflectors) made of HfO2 nanopillars are investigated to realize a large FOV at infrared wavelengths. First, the geometrical dependence of HfO2 nanopillars’ phase difference is analyzed to show the general principles of designing infrared HfO2 metasurfaces. Then, two meta-reflectors with a quadratic phase profile are investigated to show their large FOV, subwavelength resolution, and long focal depth. Furthermore, the two quadratic reflectors also show a large FOV when deflecting a laser beam with a deflecting-angle range of approximately ±80°. This study presents a flat optical metamaterial with a large FOV for imaging and deflecting, which can greatly simplify the optical–mechanical complexity of infrared systems, particularly with potential applications in high-power optical systems.

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Wide-angle vision for road views

Opto-Electronics Review ◽

10.2478/s11772-013-0079-5 ◽

2013 ◽

Vol 21 (1) ◽

pp. 1-22 ◽

Cited By ~ 3

Author(s):

F. Huang ◽

K. Fehrs ◽

G. Hartmann ◽

R. Klette

Keyword(s):

Road Safety ◽

3D Modelling ◽

Field Of View ◽

Wide Field ◽

Wide Angle ◽

Wide Field Of View ◽

Imaging Sensors

AbstractThe field-of-view of a wide-angle image is greater than (say) 90 degrees, and so contains more information than available in a standard image. A wide field-of-view is more advantageous than standard input for understanding the geometry of 3D scenes, and for estimating the poses of panoramic sensors within such scenes. Thus, wide-angle imaging sensors and methodologies are commonly used in various road-safety, street surveillance, street virtual touring, or street 3D modelling applications. The paper reviews related wide-angle vision technologies by focusing on mathematical issues rather than on hardware.

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Assessment of Stereoscopic Multi-resolution Images for a Virtual Reality System

International Journal of Virtual Reality ◽

10.20870/ijvr.2010.9.2.2769 ◽

2010 ◽

Vol 9 (2) ◽

pp. 31-37 ◽

Cited By ~ 1

Author(s):

Masahiko Ogawa ◽

Kazunori Shidoji ◽

Yuji Matsuki

Keyword(s):

High Resolution ◽

Field Of View ◽

Monitor System ◽

Wide Angle ◽

Camera System ◽

Technical Limitation ◽

Resolution Image ◽

The Gaze ◽

High Resolution Image ◽

Perceptual Characteristics

A camera and monitor system that projects actual real-world images has yet to be developed due to the technical limitation that the existing cameras cannot simultaneously acquire high-resolution and wide-angle images. In this research, we try to resolve this issue by superimposing images; a method which is effective because the entire wide-angle image does not necessarily need to be of high resolution because of perceptual characteristics of the human visual system. First, we examined the minimum resolution required for the field of view, which indicated that a triple-resolution image where positions more than 20 and 40 deg from the center of the visual field were decreased to 25% and approximately 11% of the resolution of the gaze point, respectively, was perceived as similar to a completely high-resolution image. Next, we investigated whether the participants could distinguish between the original completely high-resolution image and processed images, which included triple-resolution, dual-resolution, and low-resolution images. Our results suggested that the participants could not differentiate between the triple-resolution image and the original image. Finally, we developed a stereoscopic camera system based on our results

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Large field-of-view and compact full-Stokes polarimetry based on quadratic phase metasurface

Infrared and Laser Engineering ◽

10.3788/irla20201030 ◽

2020 ◽

Vol 49 (9) ◽

pp. 20201030-20201030

Author(s):

张雅鑫 Yaxin Zhang ◽

蒲明博 Mingbo Pu ◽

郭迎辉 Yinghui Guo ◽

靳金金 Jinjin Jin ◽

李雄 Xiong Li ◽

...

Keyword(s):

Field Of View ◽

Large Field ◽

Quadratic Phase ◽

Stokes Polarimetry

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THOR—Cloud Thickness from Offbeam Lidar Returns

Journal of Atmospheric and Oceanic Technology ◽

10.1175/jtech1740.1 ◽

2005 ◽

Vol 22 (6) ◽

pp. 605-627 ◽

Cited By ~ 33

Author(s):

Robert F. Cahalan ◽

Matthew McGill ◽

John Kolasinski ◽

Tamás Várnai ◽

Ken Yetzer

Keyword(s):

Great Plains ◽

Detection System ◽

Skin Depth ◽

Field Of View ◽

Wide Angle ◽

Southern Great Plains ◽

Diffuse Halo ◽

Atmospheric Radiation Measurement ◽

Cloud Thickness ◽

Physical Thickness

Abstract Conventional wisdom is that lidar pulses do not significantly penetrate clouds having an optical thickness exceeding about τ = 2, and that no returns are detectible from more than a shallow skin depth. Yet optically thicker clouds of τ ≫ 2 reflect a larger fraction of visible photons and account for much of the earth’s global average albedo. As cloud-layer thickness grows, an increasing fraction of reflected photons are scattered multiple times within the cloud and return from a diffuse concentric halo that grows around the incident pulse, increasing in horizontal area with layer physical thickness. The reflected halo is largely undetected by narrow field-of-view (FOV) receivers commonly used in lidar applications. Cloud Thickness from Offbeam Returns (THOR) is an airborne wide-angle detection system with multiple FOVs, capable of observing the diffuse halo as a wide-angle signal, from which the physical thickness of optically thick clouds can be retrieved. This paper describes the THOR system, demonstrates that the halo signal is stronger for thicker clouds, and presents a validation of physical thickness retrievals for clouds having τ > 20, from NASA’s P-3B flights over the Department of Energy’s Atmospheric Radiation Measurement Southern Great Plains site, using the lidar, radar, and other ancillary ground-based data.

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Object tracking with robotic total stations: Current technologies and improvements based on image data

Journal of Applied Geodesy ◽

10.1515/jag-2016-0043 ◽

2017 ◽

Vol 11 (3) ◽

Cited By ~ 3

Author(s):

Matthias Ehrhart ◽

Werner Lienhart

Keyword(s):

Object Tracking ◽

State Of The Art ◽

Image Data ◽

Field Of View ◽

Experimental Measurements ◽

Wide Angle ◽

Target Search ◽

Total Station ◽

Machine Control ◽

Wide Angle Camera

AbstractThe importance of automated prism tracking is increasingly triggered by the rising automation of total station measurements in machine control, monitoring and one-person operation. In this article we summarize and explain the different techniques that are used to coarsely search a prism, to precisely aim at a prism, and to identify whether the correct prism is tracked. Along with the state-of-the-art review, we discuss and experimentally evaluate possible improvements based on the image data of an additional wide-angle camera which is available for many total stations today. In cases in which the total station’s fine aiming module loses the prism, the tracked object may still be visible to the wide-angle camera because of its larger field of view. The theodolite angles towards the target can then be derived from its image coordinates which facilitates a fast reacquisition of the prism. In experimental measurements we demonstrate that our image-based approach for the coarse target search is 4 to 10-times faster than conventional approaches.

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