MDPI - Publisher of Open Access Journals

14 pages, 8199 KB

Open AccessFeature PaperArticle

Study of Superoscillating Functions Application to Overcome the Diffraction Limit with Suppressed Sidelobes

by Svetlana N. Khonina, Ekaterina D. Ponomareva and Muhammad A. Butt

Optics 2021, 2(3), 155-168; https://doi.org/10.3390/opt2030015 - 20 Aug 2021

Viewed by 3942

The problem of overcoming the diffraction limit does not have an unambiguously advantageous solution because of the competing nature of different beams’ parameters, such as the focal spot size, energy efficiency, and sidelobe level. The possibility to overcome the diffraction limit with suppressed sidelobes out of the near-field zone using superoscillating functions was investigated in detail. Superoscillation is a phenomenon in which a superposition of harmonic functions contains higher spatial frequencies than any of the terms in the superposition. Two types of superoscillating one-dimensional signals were considered, and simulation of their propagation in the near diffraction zone based on plane waves expansion was performed. A comparative numerical study showed the possibility of overcoming the diffraction limit with a reduced level of sidelobes at a certain distance outside the zone of evanescent waves. Full article

(This article belongs to the Special Issue Feature Papers in Optics)

► Show Figures

Figure 1

4 pages, 660 KB

Open AccessProceeding Paper

Design of a Photonic Crystal Defect Waveguide Biosensor Operating in Aqueous Solutions at 1.34 µm

by Markus Wellenzohn, Eva Melnik, Paul Muellner, Liam O’Faolain and Rainer Hainberger

Proceedings 2018, 2(13), 1026; https://doi.org/10.3390/proceedings2131026 - 14 Nov 2018

Cited by 3 | Viewed by 2294

Abstract

A two-dimensional photonic crystal defect waveguide sensor based on CMOS-compatible silicon-on-insulator technology was designed for operation in aqueous solutions at a wavelength of 1.34 µm, by the use of the 3D Plane Wave Expansion and the Finite Difference Time Domain simulation method. An operation under water in this wavelength regime allows for a significantly smaller propagation loss in contrast to the state-of-the-art operation wavelength of photonic crystals at 1.55 µm. The sensor working principle is label-free and based on evanescent wave sensing exploiting the local refractive index change induced by the specific binding of target molecules to a capture molecules immobilized on the surface of the phontonic crystal structure. We experimentally proved the theoretical predications of our simulations and demonstrated the sensing functionality of the photonic crystal defect waveguide using the biotin-straptavidin binding system. Full article

(This article belongs to the Proceedings of EUROSENSORS 2018)

► Show Figures

Figure 1

Search Results (2)

Further Information

Guidelines

MDPI Initiatives

Follow MDPI

Saved Queries

Search Filter Reset All

Years

Feature Papers

Subjects

Journals

Article Types

Countries / Regions

Search Results (2)

Further Information

Guidelines

MDPI Initiatives

Follow MDPI