Near-field scanning optical microscopy

Author(s):  
E. Betzig ◽  
A. Harootunian ◽  
M. Isaacson ◽  
A. Lewis

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.

1995 ◽  
Vol 406 ◽  
Author(s):  
A. H. La Rosa ◽  
B. I. Yakobson ◽  
H. D. Hallen

AbstractA contactless high spatial resolution technique has been developed to characterize semiconductor materials using the Near-Field Scanning Optical Microscope. The technique can be used to non-invasively measure: surface topography, defect content, and carrier lifetime variations in silicon. The success of the technique relies on the sensitive detection of changes in infrared transmission induced by local generation of free carriers using pulsed visible radiation. Here we extend the application of this technique to characterize silicon on insulator materials. We also include computer simulation results to address the role played by diffusion in the ultimate lateral resolution that can be achieved using this technique.


Open Physics ◽  
2010 ◽  
Vol 8 (3) ◽  
Author(s):  
Petr Klapetek ◽  
Juraj Bujdák ◽  
Jiří Buršík

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.


1997 ◽  
Vol 474 ◽  
Author(s):  
E. B. McDaniel ◽  
J. W. P. Hsu

ABSTRACTWe incorporate a polarization modulation technique in a near-field scanning optical microscope (NSOM) for quantitative polarimetry studies at the nanometer scale. Using this technique, we map out stress-induced birefringence associated with submicron defects at the fusion boundaries of SiTiO3 bicrystals. The strain fields surrounding these defects are larger than the defect sizes and show complex spiral shapes that break the reflection symmetry of the bicrystal boundary.


Author(s):  
E. Betzig ◽  
M. Isaacson ◽  
H. Barshatzky ◽  
K. Lin ◽  
A. Lewis

The concept of near field scanning optical microscopy was first described more than thirty years ago1 almost two decades before the validity of the technique was verified experimentally for electromagnetic radiation of 3cm wavelength.2 The extension of the method to the visible region of the spectrum took another decade since it required the development of micropositioning and aperture fabrication on a scale five orders of magnitude smaller than that used for the microwave experiments. Since initial reports on near field optical imaging8-6, there has been a growing effort by ourselves6 and other groups7 to extend the technology and develop the near field scanning optical microscope (NSOM) into a useful tool to complement conventional (i.e., far field) scanning optical microscopy (SOM), scanning electron microscopy (SEM) and scanning tunneling microscopy. In the context of this symposium on “Microscopy Without Lenses”, NSOM can be thought of as an addition to the exploding field of scanned tip microscopy although we did not originally conceive it as such.


Author(s):  
Yuan Wang ◽  
Cheng Sun ◽  
Nicholas Fang ◽  
Xiang Zhang

Recently, near-field scanning optical microscopy (NSOM) and its variations, which combine the scanning probe technology with optical microscopy, have been intensively applied in the study of biology, material science, surface chemistry, information storage, and nanofabrication. However, due to the serial scanning nature, the speed at which NSOM can successively records highly resolved images is rather limited. This hampers the applications of NSOM in characterizing dynamic response of particular samples. In this article, we perform systematic investigation of NSOM system parameters, which include scan rate, signal detector amplification, and illumination intensity. In this work, a model of signal flow for the NSOM system has been established to quantitatively investigate the interplay of the key process parameters and to further explore the technique solutions for high-speed NSOM imaging. The model is in good agreement with experimental results and the optimized conditions for high speed NSOM imaging are suggested.


1994 ◽  
Vol 2 (2) ◽  
pp. 4-4
Author(s):  
Gary Aden

Prior to Near-Field Scanning Optical Microscopy (NSOM) there were two major light microscopy techniques; optical and confocal.In an optical microscope a sample is illuminated with a flood of light. The lighted area is then imaged and magnified by collecting the light that is either reflected from or transmitted through the sample by a series of glass lenses. A color magnified image of the sample may be seen directly or displayed on a TV screen. Even if the lenses could be made perfectly, the resolution and magnification of an optical microscope are limited by diffraction effects to approximately one half of the wavelength of the light that is used. Optical microscopes are used routinely to image the general shape of samples as small as human chromosomes or compact disk bits.


Author(s):  
Eric X. Jin ◽  
Xianfan Xu

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.


2003 ◽  
Vol 02 (04n05) ◽  
pp. 225-230
Author(s):  
CHIEN-WEN HUANG ◽  
NIEN-HUA LU ◽  
CHIH-YEN CHEN ◽  
CHENG-FENG YU ◽  
TSUNG-SHENG KAO ◽  
...  

The design and construction of a tapping-mode tuning fork with a short fiber probe as the force sensing element for near-field scanning optical microscopy is reported. This type of near-field scanning optical microscopy provides a stable and high Q factor at the tapping frequency of the tuning fork, and thus gives high quality NSOM and AFM images of samples. We present results obtained by using the short tip tapping-mode tuning fork near-field scanning optical microscopy measurements performed on the endfaces of a single mode telecommunication optical fiber and a silica-based buried channel waveguide.


1999 ◽  
Vol 5 (S2) ◽  
pp. 390-391
Author(s):  
Levi A. Gheber ◽  
Michael Edidin

Near Field Scanning Optical Microscopy (NSOM) is the newest member of the Scanning Probe Microscopy (SPM) family, which includes Scanning Tunneling Microscopy (STM) and Atomic Force Microscopy (AFM). Like its predecessors, it uses a sharp tip and a very precise positioning system to scan the surface of samples. The important difference is that the NSOM tip is made of an optical fiber, with a sub-wavelength size aperture at its end, which is brought to near-field proximity to the sample. In the near-field regime, the resolution is only limited by the size of the light source (the aperture), and not by the wavelength of light, thus allowing NSOM to obtain images with subwavelength resolution. Applying NSOM to biological samples is very appealing, since biological research has developed a wide variety of fluorescent dyes which can be directed with high specificity to objects of interest. Moreover, biological research relies to a large extent on conventional fluorescence microscopy, which is diffraction limited. Application of NSOM to biological problems requires the ability to image rough and soft samples in liquid, a task that presents many challenges.We have developed a NSOM which is capable of imaging cells in liquid with a resolution of ∼150 nm. This has enabled us to image the organization of fluorescently labeled proteins on the membrane of cells in liquid, and demonstrate for the first time that the proteins are clustered.


2006 ◽  
Vol 14 (5) ◽  
pp. 28-31
Author(s):  
Erik J. Sanchez

Recent advances in nanotechnology and nanoscience are highly dependent on our newly acquired ability to measure and manipulate individual structures on the nanoscale. A drawback of light microscopy is the fundamental limit of the attainable spatial resolution dictated by the laws of diffraction at about 250 nanometers. This diffraction limit arises from the fact that it is impossible to focus light to a spot smaller than half its wavelength. The challenge of breaking this limit has led to the development of near-field scanning optical microscopy (NSOM).


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