Near-field evanescent waves scattered from a spatially deterministic and anisotropic medium

2015 ◽  
Vol 40 (12) ◽  
pp. 2680 ◽  
Author(s):  
Jia Li ◽  
Liping Chang ◽  
Zhefu Wu
Keyword(s):  
Anisotropic Medium ◽  
Near Field ◽  
Evanescent Waves

UV laser-assisted multiple evanescent waves lithography for near-field nanopatterning

2009 ◽  
Vol 4 (4) ◽  
pp. 210-214 ◽  
Author(s):  
J.K. Chua ◽  
V.M. Murukeshan
Keyword(s):  
Near Field ◽  
Evanescent Waves ◽  
Uv Laser

scholarly journals Generation of UV Photons Produced by Lightning in Vacuum Conditions:

2019 ◽  
Vol 4 (9) ◽  
pp. 78-80
Author(s):  
Omar Rodriguez Pinilla ◽  
Wilmar Hernández
Keyword(s):  
Anisotropic Medium ◽  
Near Field ◽  
Lightning Discharge ◽  
Quantum Model ◽  
Uv Photons ◽  
Theoretical Proposal

In the following work, a theoretical proposal is presented on the mechanism of generation UV photons produced by lightning in vacuum conditions under anisotropic medium (gas) using the quantum model of near field electrodynamics through paths integrals. The aim is calculate and sensing the number of photons that can generate a lightning discharge under a voltage of 2000 volts AC in t seconds

scholarly journals Progress towards the realization of an optical Far-Field Superlens

2021 ◽  
Author(s):  
◽  
Farzaneh Fadakar Masouleh
Keyword(s):  
Zinc Oxide ◽  
Near Field ◽  
Diffraction Gratings ◽  
Evanescent Waves ◽  
Field Pattern ◽  
Far Field ◽  
Potential Candidate ◽  
Plasmonic Material ◽  
Far Field Pattern ◽  
The Impact

<p>Conventional optics suffer from a fundamental resolution limit due to the nature of light. The near-field superlens concept was introduced two decades ago, and its theory for enabling high resolution imaging is well-established now. Initially, this superlens, which has a simple setup, became a hot topic given the proposition of overcoming the diffraction limit. It has been demonstrated that a near-field superlens can reconstruct images using evanescent waves emanating from small objects by means of resonant excitations on the surface of the superlens. A modified version of the superlens named the far-field superlens is theorized to be able to project the near-field subwavelength information to the far-field region. By design, the far-field superlens is a near-field superlens with nanostructures added on top of it. These nanostructures, referred to as diffraction gratings help couple object information available in the evanescent waves to the far-field. Work reported in this thesis is divided to two major sections. The first describes the modelling technique that investigates the performance of a far-field superlens. This section focuses on evaluating the impact of the diffraction gratings geometry and the object size on the far-field superlens performance as well as the resulting far-field pattern. It was shown that a far-field superlens with a nanograting having a duty cycle of 40% to 50% produces the maximum intensity and contrast in the far-field interactions. For periodic rectangular objects, an inverse-trapezoidal nanograting was shown to provide the best contrast and intensity for far-field interactions. The minimal simulation domain to model a symmetric far-field superlens design was determined both in 2D and 3D. This input reduced the required modelling time and resources. Finally, a 3D far-field superlens model was proposed, and the effect of light polarization on the far-field pattern was studied. The second section of this thesis contains the experimental study that explores a new material as a potential candidate for the construction of far-field superlens. The material conventionally used for superlens design is silver, as its plasmonic properties are well-established. However, scaling down silver features to the nanoscale introduces fundamental fabrication challenges. Furthermore, silver oxidizes due to its reactions with sulphur compounds at ambient conditions, which means that operating a silver far-field superlens is only possible in a well-controlled environment. This disagrees with our proposed concept of a low-cost and robust superlens imaging device. On the other hand, highly doped semiconductors are emerging candidates for plasmonic applications due to the possibility of tuning their optical and electrical properties during the fabrication process. While the working principle of a superlens is independent of the plasmonic material of choice, every plasmonic material has a particular range of operating wavelengths. The pros and cons of each plasmonic material are usually identified once used experimentally. In this work, aluminium-doped zinc oxide was the proposed material of choice for the far-field superlens design. The second part of this thesis details the characterization results of the optical, electrical and structural properties of this proposed alternative. Our aluminium-doped zinc oxide samples were highly transparent for large parts of the spectrum. Their carrier concentration was of the order of 10+20 cm-3, and a resistivity of about 10-3 Ω.cm was achieved. The modelled dielectric permittivity for the studied samples showed a cross-over frequency in the near-infrared region, with the highest plasma frequency achieved in this study being 4710 cm-1.</p>

scholarly journals Transfer function and near-field detection of evanescent waves

2006 ◽  
Vol 45 (17) ◽  
pp. 4054 ◽  
Author(s):  
Ilya P. Radko ◽  
Sergey I. Bozhevolnyi ◽  
Niels Gregersen
Keyword(s):  
Transfer Function ◽  
Near Field ◽  
Evanescent Waves ◽  
Field Detection

scholarly journals Impact of the evanescent waves on the backflow of power in the near field

2019 ◽  
Vol 1368 ◽  
pp. 022065
Author(s):  
V V Kotlyar ◽  
A A Kovalev ◽  
D S Kalinkina
Keyword(s):  
Near Field ◽  
Evanescent Waves

PASSIVELY DETECTING THERMAL EVANESCENT WAVES FROM ROOM TEMPERATURE OBJECTS

2010 ◽  
Vol 19 (04) ◽  
pp. 589-594 ◽  
Author(s):  
YUSUKE KAJIHARA ◽  
KEISHI KOSAKA ◽  
SUSUMU KOMIYAMA
Keyword(s):  
Shear Force ◽  
Electrochemical Etching ◽  
Signal To Noise Ratio ◽  
Near Field ◽  
Infrared Region ◽  
Optical Microscope ◽  
Evanescent Waves ◽  
Highly Sensitive ◽  
Force Mode ◽  
Averaging Time

We have developed a scattering-type scanning near-field optical microscope in long-wavelength infrared region (wavelength: λ ~ 14.5 μm) with a highly sensitive detector, named charge sensitive infrared phototransistor. A tungsten near-field probe was fabricated via electrochemical etching and the sample-probe distance was precisely controlled in shear-force mode. By vertically modulating the probe independently of lateral oscillation for shear-force mode, we successfully detected thermal evanescent waves from a 3 μm-pitch Au/GaAs grating without any external illumination. The spatial resolution was experimentally estimated to be better than 150 nm (λ/100) and the signal-to-noise ratio was around 4 with an averaging time of 300 ms. The strong near-field signal from Au was suggested to be ascribed to thermally excited surface plasmons generating evanescent waves at the surface.

DIFFRACTION OF 3.2 CM. ELECTROMAGNETIC WAVES BY DIELECTRIC RODS: III. LUCITE IN. DIAMETER SEMICYLINDER, FIELDS VERY CLOSE TO SURFACE

1957 ◽  
Vol 35 (11) ◽  
pp. 1253-1264 ◽  
Author(s):  
A. B. McLay ◽  
C. E. Jordan
Keyword(s):  
Electromagnetic Waves ◽  
Plane Surface ◽  
Near Field ◽  
Aluminum Foil ◽  
Evanescent Waves ◽  
Incident Field ◽  
Thin Aluminum ◽  
Diffraction Patterns ◽  
Thin Aluminum Foil

The diffraction fields near a long, semicylindrical, [Formula: see text] in. diameter rod of lucite, oriented in a nearly plane incident field of 3.2 cm. waves with plane surface towards or away from the source, have been reinvestigated in the region very close to the rod more thoroughly than previously (McLay and Subbarao 1956). The incident field was polarized parallel to the long axis of the semicylinder. In addition, the field near the rod when it was oriented with plane surface aligned with the axis of propagation and the field when the same rod was coated with thin aluminum foil and placed in turn in each of the three above-mentioned orientations have now been observed.A number of features in the diffraction patterns of the uncoated lucite rod have been qualitatively accounted for as resulting from effects of weak radiation after one or more internal reflections, or from evanescent waves close to a part of the surface where internal incidence is at angles greater than critical, superposed on one or more of the incident, directly transmitted and externally reflected radiations. The patterns a little away from the surface of the uncoated rod and the whole patterns of the aluminum-coated one are quite simple relatively and provide evidence of marked near-field diffraction.

scholarly journals Near-Field Spot for Localized Light-Excitation of a Single Fluorescent Molecule

2020 ◽  
Vol 10 (4) ◽  
pp. 364-374
Author(s):  
Muhammad Shemyal Nisar ◽  
Yujun Cui ◽  
Kaitong Dang ◽  
Liyong Jiang ◽  
Xiangwei Zhao
Keyword(s):  
Single Molecule ◽  
Degrees Of Freedom ◽  
Zero Mode ◽  
Near Field ◽  
3D Structure ◽  
Single Molecules ◽  
Evanescent Waves ◽  
Water Interface ◽  
Large Molecules ◽  
Light Excitation

Abstract Zero-mode waveguides have become important tools for the detection of single molecules. There are still, however, serious challenges because large molecules need to be packed into nano-holes. To circumvent this problem, we investigate and numerically simulate a novel planar sub-wavelength 3-dimension (3D) structure, which is named as near-field spot. It enables the detection of a single molecule in highly concentrated solutions. The near-field spot can produce evanescent waves at the dielectric/water interface, which exponentially decay as they travel away from the dielectric/water interface. These evanescent waves are keys for the detection of fluorescently tagged single molecules. A numerical simulation of the proposed device shows that the performance is comparable with a zero-mode waveguide. Additional degrees-of-freedom, however, can potentially supersede its performance.

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