Superresolution far-field imaging of complex objects using reduced superoscillating ripples

Author(s):

Xiao Han Dong and Alex M. H. Wong and Minseok Kim and George V. Eleftheriades

Abstract:

“Superoscillation is a phenomenon where a wave oscillates locally faster than its highest Fourier component. While previous reports have shown attractive possibilities for a superoscillation-based far-field superresolution imaging device, it has also been recognized that a high-energy “sideband” region coexists with the superresolution features. This sideband causes strong restrictions and necessitates trade-offs in achievable resolution, viewing area, and sensitivity of the imaging device. In this work, we introduce a new class of superoscillation waveform—which consists of a diffraction-limited hotspot surrounded by low-energy superoscillating sidelobe ripples. This waveform alleviates the aforementioned trade-off and enables superresolution imaging for complex objects over a larger viewing area while maintaining a practical level of sensitivity. Using this waveform as the point spread function of an imaging system, we demonstrate the successful superresolution of Latin letters without performing scanning and/or post-processing operations.”

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Publication: Optica

Issue/Year/DOI: Optica, Vol. 4, Issue 9, pp. 1126-1133 (2017)
DOI: 10.1364/OPTICA.4.001126

Silver Nanowires for Reconfigurable Bloch Surface Waves.

Author(s):

Zhang, Douguo and Wang, Ruxue and Xiang, Yifeng and Kuai, Yan and Kuang, Cuifang and Badugu, Ramachandram and Xu, Yingke and Wang, Pei and Ming, Hai and Liu, Xu and Lakowicz, Joseph R.

Abstract:

“The use of a single silver nanowire as a flexible coupler to transform a free space beam into a Bloch surface wave propagating on a dielectric multilayer is proposed. Based on Huygens ‘Principle, when a Gaussian beam is focused onto a straight silver nanowire, a Bloch surface wave is generated and propagates perpendicular to the nanowire. By curving the silver nanowire, the surface wave can be focused. Furthermore, the spatial phase of the incident laser beam can be actively controlled with the aid of a spatial light modulator, resulting in the reconfigurable or dynamically controlled Bloch surface waves. The low cost of the chemically synthesized silver nanowires and the high flexibility with regard to tuning the spatial phase of the incident light make this approach very promising for various applications including optical micromanipulation, fluorescence imaging, and sensing.”

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Publication: ACS Nano

Issue/Year/DOI:  ACS Nano, 2017, 11 (10), pp 10446–10451
DOI: 10.1021/acsnano.7b05638

Programmable Vector Mode Multiplexer

Author(s): N. K. Fontaine and H. Chen and R. Ryf and D. Neilson and J. C. Alvarado and J. van Weerdenburg and R. Amezcua-Correa and C. Okonkwo and J. Carpenter

Abstract:

“We demonstrate a programmable vector mode multiplexer using a low-loss spatial light phase modulator that can multiplex 10 modes. It is reconfigured to generate modes for multi-mode fiber and modes with arbitrary polarization including linear, radial, and azimuthal.”

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Publication: 2017 European Conference on Optical Communication (ECOC)

Issue/Year/DOI: 2017 European Conference on Optical Communication (ECOC)
DOI: 10.1109/ECOC.2017.8346099

Dynamic three-dimensional multifocal spots in high numerical-aperture objectives

Author(s):

Linwei Zhu and Rui Yang and Dawei Zhang and Junjie Yu and Jiannong Chen

Abstract:

“Multifocal spots in high numerical-aperture (NA) objectives has emerged as a rapid, parallel, and multi-location method in a multitude of applications. However, the typical method used for forming three-dimensional (3D) multifocal spots based on iterative algorithms limits the potential applications. We demonstrate a non-iterative method using annular subzone phases (ASPs) that are composed of many annular subareas in which phase-only distributions with different 3D displacements are filled. The dynamic 3D multifocal spots with controllable position of each focal spot in the focal volume of the objective are created using the ASPs. The experimental results of such dynamic tunable 3D multifocal spots offer the possibility of versatile process in laser 3D fabrication, optical trapping, and fast focusing scanned microscopic imaging.”

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Publication: Optics Express

Issue/Year/DOI: Optics Express, Vol. 25, Issue 20, pp. 24756- 24766 (2018)
DOI: 10.1364/OE.25.024756