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We study numerically, by means of the pseudospectral time-domain method, the unique features of imaging by a flat lens made of a left-handed metamaterial that possesses the property of negative refraction. We confirm the earlier finding…

Optics · Physics 2009-11-10 Michael W. Feise , Yuri S. Kivshar

For distant iris recognition, a long focal length lens is generally used to ensure the resolution ofiris images, which reduces the depth of field and leads to potential defocus blur. To accommodate users at different distances, it is…

Computer Vision and Pattern Recognition · Computer Science 2021-06-30 Leyuan Wang , Kunbo Zhang , Yunlong Wang , Zhenan Sun

In this paper we compare the sensitivity of two imaging configurations both based on Laser Optical Feedback Imaging (LOFI). The first one is direct imaging, which uses conventional optical focalisation on target and the second one is made…

In this paper, a two-dimensional cylindrical Lens antenna based on the parallel plate technique is designed. It supports beam-steering capability of 58 degree at 28 GHz. The antenna is composed of low loss rectangular waveguide antennas,…

Signal Processing · Electrical Eng. & Systems 2019-03-28 Saeideh Shad , Shafaq Kausar , Hani Mehrpouyan

We present a fully differentiable framework for seamlessly integrating wave optical components with geometrical lenses, offering an approach to enhance the performance of large-scale end-to-end optical systems. In this study, we focus on…

Optics · Physics 2023-08-02 Ziwei Zhu , Zhaocheng Liu , Changxi Zheng

Spin glasses are paradigmatic models that deliver concepts relevant for a variety of systems. However, rigorous analytical results are difficult to obtain for spin-glass models, in particular for realistic short-range models. Therefore…

Disordered Systems and Neural Networks · Physics 2008-02-12 Helmut G. Katzgraber

Motivated by their great potential to reduce the size, cost and weight, flat lenses, a category that includes diffractive lenses and metalenses, are rapidly emerging as key components with the potential to replace the traditional refractive…

Optics · Physics 2023-08-25 Roy Maman , Eitan Mualem , Noa Mazurski , Jacob Engelberg , Uriel Levy

New type of lenses which are a slab of a left-handed material embedded into a regular material is proposed. These two materials should have equal refractive indices. Lenses with a focal length larger than the width of the slab can be…

Condensed Matter · Physics 2007-05-23 A. L. Pokrovsky , A. L. Efros

Quantitative estimates of lensing probabilities must be self-consistent. In particular, for asymptotically isothermal models: (1) using the $(3/2)^{1/2}$ correction for the velocity dispersion overestimates the expected number of lenses by…

Astrophysics · Physics 2007-05-23 C. S. Kochanek

Lenses with dynamic focal length, also called zoom functionality, enable a variety of applications related to imaging and sensing. The traditional approach of stacking refractive lenses to achieve this functionality results in an expensive,…

The vast progress in synthetic image synthesis enables the generation of facial images in high resolution and photorealism. In biometric applications, the main motivation for using synthetic data is to solve the shortage of…

Computer Vision and Pattern Recognition · Computer Science 2022-08-18 Marcel Grimmer , Haoyu Zhang , Raghavendra Ramachandra , Kiran Raja , Christoph Busch

Focusing properties of a novel type photoresist microlens are studied. A specific character of the microlens is its mushroom shape. Recently it was predicted and experimentally revealed that such a lens integrated with a light-emitting…

Optics · Physics 2010-01-19 A. V. Boriskin , S. V. Boriskina , T. Benson , P. Sewell , A. I. Nosich

Recent advances in meta-optics have enabled diverse functionalities in compact optical devices; however, conventional forward design approaches become inadequate as device complexity and scale grow. Inverse design offers a powerful…

A wide choice of cinematic lenses enables motion-picture creators to adapt image visual-appearance to their creative vision. Such choice does not exist in the realm of real-time computer graphics, where only one type of perspective…

Graphics · Computer Science 2024-02-09 Jakub Maksymilian Fober

Compact radio sources have been observed to undergo large, frequency dependent changes in intensity due to lensing by structures in the interstellar medium, in so-called "extreme scattering events" (ESEs). While the study of astrophysical…

High Energy Astrophysical Phenomena · Physics 2022-06-22 Dylan L. Jow , Ue-Li Pen

Dimensionality reduction algorithms are often used to visualise high-dimensional data. Previously, studies have used prior information to enhance or suppress expected patterns in projections. In this paper, we adapt such techniques for…

Machine Learning · Computer Science 2024-05-16 Daniel M. Bot , Jan Aerts

A multi-prism lens (MPL) is a refractive x-ray lens with one-dimensional focusing properties. If used as a pre-object collimator in a scanning system for medical x-ray imaging, it reduces the divergence of the radiation and improves on…

Medical Physics · Physics 2021-01-21 Erik Fredenberg , Bjorn Cederstrom , Magnus Aslund , Peter Nillius , Mats Danielsson

We describe the most general homogenous, planar, light-ray-direction-changing sheet that performs one-to-one imaging between object space and image space. This is a non-trivial special case (of the sheet being homogenous) of an earlier…

Optics · Physics 2015-06-17 Stephen Oxburgh , Johannes Courtial

We present a method that leverages the complementarity of event cameras and standard cameras to track visual features with low-latency. Event cameras are novel sensors that output pixel-level brightness changes, called "events". They offer…

Computer Vision and Pattern Recognition · Computer Science 2019-01-21 Daniel Gehrig , Henri Rebecq , Guillermo Gallego , Davide Scaramuzza

Gradient index sonic lenses based on two-dimensional sonic crystals are here designed, fabricated and characterized. The index-gradient is achieved in these type of flat lenses by a gradual modification of the sonic crystal filling fraction…

Materials Science · Physics 2015-05-19 Alfonso Climente , Daniel Torrent , Jose Sanchez-Dehesa