The scanning electron microscope and its fields of application

Smith, K.C.; Oatley, C.W.

doi:10.1088/0508-3443/6/11/304

Cited by 222 publications

(66 citation statements)

References 3 publications

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“…5. (Optional) To map the GNSs on the glass with high resolution, perform scanning electron microscopy (SEM) at this stage 23 . An example image is provided in Figure 1, showing the characteristic density of GNSs.…”

Section: Gns Sample Preparationmentioning

confidence: 99%

Measurement of Scattering Nonlinearities from a Single Plasmonic Nanoparticle

Lee

Huang

et al. 2016

JoVE

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Plasmonics, which are based on the collective oscillation of electrons due to light excitation, involve strongly enhanced local electric fields and thus have potential applications in nonlinear optics, which requires extraordinary optical intensity. One of the most studied nonlinearities in plasmonics is nonlinear absorption, including saturation and reverse saturation behaviors. Although scattering and absorption in nanoparticles are closely correlated by the Mie theory, there has been no report of nonlinearities in plasmonic scattering until very recently.Last year, not only saturation, but also reverse saturation of scattering in an isolated plasmonic particle was demonstrated for the first time. The results showed that saturable scattering exhibits clear wavelength dependence, which seems to be directly linked to the localized surface plasmon resonance (LSPR). Combined with the intensity-dependent measurements, the results suggest the possibility of a common mechanism underlying the nonlinear behaviors of scattering and absorption. These nonlinearities of scattering from a single gold nanosphere (GNS) are widely applicable, including in super-resolution microscopy and optical switches.In this paper, it is described in detail how to measure nonlinearity of scattering in a single GNP and how to employ the super-resolution technique to enhance the optical imaging resolution based on saturable scattering. This discovery features the first super-resolution microscopy based on nonlinear scattering, which is a novel non-bleaching contrast method that can achieve a resolution as low as l/8 and will potentially be useful in biomedicine and material studies. Video LinkThe video component of this article can be found at

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Section: Gns Sample Preparationmentioning

confidence: 99%

Measurement of Scattering Nonlinearities from a Single Plasmonic Nanoparticle

Lee

Huang

et al. 2016

JoVE

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“…The scanning microscope operates by focusing the electron beam into a probe which is scanned across the specimen, while a detected signal resulting from electron interaction with the specimen is used to modulate the intensity on a synchronously scanned display tube. It has become widely used in the secondary emission mode, whereby slow secondary electrons ejected from the surface of thick specimens are detected (8). The resolution limit of these secondary emission microscopes is, however, determined not by the lenses used, but by the electron sources, which are generally hot tungsten filaments, of insufficient inherent brightness to provide adequate current in a diffraction limited spot.…”

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confidence: 99%

Scanning Transmission Electron Microscopy at High Resolution

Wall

Langmore

Isaacson

et al. 1974

Proc. Natl. Acad. Sci. U.S.A.

124

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We have shown that a scanning transmission electron microscope with a high brightness field emission source is capable of obtaining better than 3 A resolution using 30 to 40 keV electrons. Elastic dark field images of single atoms of uranium and mercury are shown which demonstrate this fact as determined by a modified Rayleigh criterion. Point-to-point micrograph resolution between 2.5 and 3.0 A is found in dark field images of micro-crystallites of uranium and thorium compounds. Furthermore, adequate contrast is available to observe single atoms as light as silver.The ability to obtain high resolution images of very small objects is of considerable importance in the biological and material sciences. The only instrument heretofore available for this purpose has been the conventional transmission electron microscope (CTEM).Invented in the 1930's, the basic design of this instrument is an electron analog of the light microscope. The performance of the CTEM has steadily improved during the last few decades, and it is now limited primarily by diffraction effects and the large aberrations inherent in electromagnetic lenses.For the moment, we will ignore the effects of chromatic aberration. This is justifiable if the electron energy is high enough. Then one can minimize the combined effect of diffraction and spherical aberration to calculate the objective aperture which gives the best instrumental resolution. In this case, a hypothetical point source of scattered electrons in the specimen plane would be imaged as a modified Airy disc whose radius to the first intensity minimum is given by a = 0.43 Cs1/4X" [1] where C, is the coefficient of spherical aberration (generally of the order of 1 mm in high quality objective lenses) and X is the wavelength of the incident electron (0.037 A for 100-keV electrons) (1). The image of two incoherent point objects separated by this distance 6 will have an intensity minimum between them of 0.75 of the peak intensity and will be resolved according to the modified Rayleigh criterion of Scherzer (1). In order to obtain this resolution, the objective aperture should subtend a half-angle at the specimen given by (2) a(pt = (4X/Cs) 1/4.

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“…Further work was reported by Zworykin's group (Zworykin et al, 1942) followed by the Cambridge groups in the 1950s and early 1960s (McMullan, 1953;Oatley et al, 1965;Smith and Oatley, 1955;Wells, 1957) headed by Charles Oatley et al, (1965) all of which finally led to the marketing of the first commercial instrument by Cambridge Scientific Instrument Company as the "Stereoscan" in 1965 (delivered to DuPont).…”

Section: Introductionmentioning

confidence: 99%