Obtaining Subwavelength Optical Spots Using Nanoscale Ridge Apertures

Concentrating light into a nanometer domain is needed for optically based materials processing at the nanoscale. Conventional nanometer-sized apertures suffer from low light transmission, therefore poor near-field radiation. It has been suggested that ridge apertures in various shapes can provide enhanced transmission while maintaining the subwavelength optical resolution. In this work, the near-field radiation from an H-shaped ridge nanoaperture fabricated in an aluminum thin film is experimentally characterized using near-field scanning optical microscopy. With the incident light polarized along the direction across the gap in the H aperture, the H aperture is capable of providing an optical spot of about 106nm by 80nm in full-width half-maximum size, which is comparable to its gap size and substantially smaller than those obtained from the square and rectangular apertures of the same opening area. Finite different time domain simulations are used to explain the experimental results. Variations between the spot sizes obtained from a 3×3 array of H apertures are about 4–6%. The consistency and reliability of the near-field radiation from the H apertures show their potential as an efficient near-field light source for materials processing at the nanoscale.

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Measurement of Radiation Transfer Through Nano-Apertures Using Near-Field Scanning Optical Microscopy

Heat Transfer, Part B ◽

10.1115/imece2005-83059 ◽

2005 ◽

Cited By ~ 1

Author(s):

Eric X. Jin ◽

Xianfan Xu

Keyword(s):

Near Field ◽

Optical Resolution ◽

Optical Microscope ◽

Aluminum Film ◽

Optical Recording ◽

Enhanced Transmission ◽

Ultrahigh Density ◽

Scanning Optical Microscopy ◽

Near Field Scanning ◽

Made In

Ridge apertures in various shapes have attracted extensive studies which showed their potential capabilities in realizing both enhanced transmission and nanoscale optical resolution, therefore, enabling ultrahigh density near-field optical recording. In this work, the optical near field distributions of an H-shaped ridge aperture and comparable regular apertures made in aluminum film are experimentally investigated using a home-made near-field scanning optical microscope. With a sub-100 nm aperture probe, the full-width half-magnitude (FWHM) near-field spot of the H aperture is measured as 106 nm by 80 nm, comparable to the gap size but substantially smaller than that obtained from a square aperture with the same area. The elongated near-field light spot in the direction across the ridges is due to the scattering of the transmitted light on the edges based on results of numerical calculations.

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Near-field scanning optical microscopy local luminescence studies of rhodamine dye

Open Physics ◽

10.2478/s11534-009-0109-6 ◽

2010 ◽

Vol 8 (3) ◽

Cited By ~ 1

Author(s):

Petr Klapetek ◽

Juraj Bujdák ◽

Jiří Buršík

Keyword(s):

Time Domain ◽

Near Field ◽

Optical Microscope ◽

Far Field ◽

Luminescence Signal ◽

Local Topography ◽

Field Radiation ◽

Scanning Optical Microscopy ◽

Rhodamine Dye ◽

Near Field Scanning

AbstractThis article presents results of near-field scanning optical microscope measurement of local luminescence of rhodamine 3B intercalated in montmorillonite samples. We focus on how local topography affects both the excitation and luminescence signals and resulting optical artifacts. The Finite Difference in Time Domain method (FDTD) is used to model the electromagnetic field distribution of the full tip-sample geometry including far-field radiation. Even complex problems like localized luminescence can be simulated computationally using FDTD and these simulations can be used to separate the luminescence signal from topographic artifacts.

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Plasmonic-Enhanced Radiative Transfer Through Nanoscale Aperture Antennas

Heat Transfer, Volume 1 ◽

10.1115/imece2006-13778 ◽

2006 ◽

Author(s):

Eric X. Jin ◽

Liang Wang ◽

Xianfan Xu

Keyword(s):

Radiative Transfer ◽

Near Field ◽

Transfer Efficiency ◽

Aperture Antenna ◽

Plasmon Excitation ◽

Aperture Antennas ◽

Radiation Enhancement ◽

Field Radiation ◽

Scanning Optical Microscopy ◽

Near Field Scanning

Nanoscale ridge aperture antenna as a nanoscale high transmission optical device is demonstrated. High transfer efficiency and confined radiation are achieved simultaneously in the near field compared with regularly-shaped apertures. The radiation enhancement is attributed to the fundamental electromagnetic field propagating in the TE10 mode concentrated in the gap between the ridges. The transfer efficiency is further enhanced through plasmon excitation and resonance. This paper reports spectroscopic measurements of radiative transfer through bowtie shape ridge aperture antennas. Resonance in these aperture antennas and its relation with the aperture geometry are investigated. The near-field radiation through the bowtie aperture and the regular nanoaperture is also mapped with near-field scanning optical microscopy. It is revealed that plasmon excitation and resonance contribute to the radiation enhancement through the ridge aperture antennas.

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Resolution in near-field optical microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010008657x ◽

1991 ◽

Vol 49 ◽

pp. 454-455

Author(s):

M. Isaacson

Keyword(s):

Optical Microscopy ◽

Near Field ◽

Optical Resolution ◽

Super Resolution ◽

Optical Probe ◽

Basic Principles ◽

Scanning Optical Microscopy ◽

Super Resolution Microscopy ◽

Near Field Scanning ◽

Probe Source

It has only been within the last half decade that the concept of super resolution microscopy in the near-field has been vigorously pursued and experimentally demonstrated. However, the idea of optical resolution unhindered by far field diffraction limitations was conceived more than a half century ago by Synge and further elaborated by O'Keefe in the fifties. That die method was possible, however, was only first demonstrated using 3cm wavelength microwaves almost 20 years later.The basic principles of the method of near field scanning optical microscopy (NSOM) have been described before in the literature. Briefly, the idea is as follows: if an optical probe (source or detector) of diameter D is positioned within a distance of approximately D/π from the surface of an object, and the reflected, transmitted or emitted light is detected, then the lateral spatial region from which the information occurs is limited to aregion of approximate size D and not by the wavelength of the illuminated or detected light.

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Near-field scanning optical microscopy imaging of luminescent polymers

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100166762 ◽

1996 ◽

Vol 54 ◽

pp. 860-861

Author(s):

J. Kerimo ◽

D. A. Vanden Bout ◽

D. A. Higgins ◽

P.F. Barbara

Keyword(s):

Organic Semiconductors ◽

Near Field ◽

Practical Importance ◽

Numerical Aperture ◽

Optical Resolution ◽

Microscopy Imaging ◽

Light Emitting ◽

Scanning Optical Microscopy ◽

Luminescent Polymer ◽

Near Field Scanning

Conjugated polymers such as poly(p-pyridyl vinylene)(PPyV) have interesting photoluminescence and electroluminescence properties. These polymers have a high quantum yield of luminescence and are of great practical importance as light-emitting diodes or organic semiconductors. We have performed studies on thin films(about 50nm) of these polymers using the high spatial optical resolution of NSOM.The luminescent polymer film was excited with 488nm light and the fluorescence was collected with a high numerical aperture microscope objective. Topography and NSOM fluorescence images were collected simultaneously and used for studying the morphology and optical properties of the film. An example of topography and fluorescence NSOM images of the film is shown in Fig. 1a. The films are very flat (2nm rms variations in topography) and have very few features. The NSOM fluorescence image shows great film inhomogeneity with bright features varying in size from 80-250nm observed throughout (Fig. 1b). These features do not correlate with the topography, indicating they may be located in the bulk of the polymer or are simply not resolvable in the topography image.

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Influence of probe tip size and incident light polarization on resolution in near-field scanning optical microscopy

10.1117/12.577201 ◽

2005 ◽

Author(s):

Guiying Wang ◽

Qinghua Wu ◽

Zhizhan Xu

Keyword(s):

Optical Microscopy ◽

Incident Light ◽

Near Field ◽

Light Polarization ◽

Scanning Optical Microscopy ◽

Near Field Scanning

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Plasmonic-Enhanced Radiative Transfer Through Nanoscale Aperture Antennas

First International Conference on Integration and Commercialization of Micro and Nanosystems, Parts A and B ◽

10.1115/mnc2007-21589 ◽

2007 ◽

Author(s):

Eric X. Jin ◽

Liang Wang ◽

Xianfan Xu

Keyword(s):

Radiative Transfer ◽

Near Field ◽

Transfer Efficiency ◽

Aperture Antenna ◽

Plasmon Excitation ◽

Aperture Antennas ◽

Radiation Enhancement ◽

Field Radiation ◽

Scanning Optical Microscopy ◽

Near Field Scanning

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Near-field scanning optical microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100144644 ◽

1986 ◽

Vol 44 ◽

pp. 642-643

Author(s):

E. Betzig ◽

A. Harootunian ◽

M. Isaacson ◽

A. Lewis

Keyword(s):

Near Field ◽

Optical Microscope ◽

Visible Radiation ◽

Field Methods ◽

Optical Elements ◽

Optical Region ◽

Order Of Magnitude ◽

Nondestructive Imaging ◽

Scanning Optical Microscopy ◽

Near Field Scanning

In general, conventional methods of optical imaging are limited in spatial resolution by either the wavelength of the radiation used or by the aberrations of the optical elements. This is true whether one uses a scanning probe or a fixed beam method. The reason for the wavelength limit of resolution is due to the far field methods of producing or detecting the radiation. If one resorts to restricting our probes to the near field optical region, then the possibility exists of obtaining spatial resolutions more than an order of magnitude smaller than the optical wavelength of the radiation used. In this paper, we will describe the principles underlying such "near field" imaging and present some preliminary results from a near field scanning optical microscope (NS0M) that uses visible radiation and is capable of resolutions comparable to an SEM. The advantage of such a technique is the possibility of completely nondestructive imaging in air at spatial resolutions of about 50nm.

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