scholarly journals Influence of Illumination Polarization and Target Structure on Measurement Sensitivity of Through-Focus Scanning Optical Microscopy

2018 ◽  
Vol 8 (10) ◽  
pp. 1819 ◽  
Author(s):  
Yufu Qu ◽  
Renju Peng ◽  
Jialin Hao ◽  
Hui Pan ◽  
Jiebin Niu ◽  
...  
Keyword(s):  
Optical Microscopy ◽  
Three Dimensional ◽  
Polarized Light ◽  
Target Structure ◽  
Measurement Sensitivity ◽  
Dimensional Inspection ◽  
Asymmetric Structures ◽  
Enhanced Sensitivity ◽  
Focus Image ◽  
Scanning Optical Microscopy

Unlike the optical information taken from a single in-focus image of general optical microscopy, through-focus scanning optical microscopy (TSOM) involves scanning a target through the focus and capturing of a series of images. These images can be used to conduct three-dimensional inspection and metrology with nanometer-scale lateral and vertical sensitivity. The sensitivity of TSOM strongly depends on many mechanical and optical factors. In this study, how illumination polarization and target structure affect the sensitivity of TSOM is analyzed. Firstly, the complete imaging procedure of the polarized light is investigated. Secondly, through-focus scanning results of different targets with two illumination polarizations are simulated using the finite-difference time-domain method. Thirdly, a few experiments are performed to verify the influence of illumination polarization and target structures on the sensitivity of TSOM. Both the results of the simulation and experiments illustrate an apparent influence of polarization on the sensitivity of inspecting the targets with center asymmetric structures. For enhanced sensitivity, illumination polarization should be perpendicular to the target texture. This conclusion is meaningful to adjust illumination polarization purposefully for different structure characteristics and improve the sensitivity of metrology.

Optics, Optical Methods, and Microscopy

2021 ◽  
pp. 345-407
Author(s):  
Kannan M. Krishnan
Keyword(s):  
Optical Microscopy ◽  
Polarization State ◽  
Three Dimensional ◽  
Polarized Light ◽  
Dark Field ◽  
Optical Methods ◽  
Transverse Waves ◽  
Dark Field Imaging ◽  
Propagation Of Light ◽  
Scanning Optical Microscopy

Propagation of light is described as the simple harmonic motion of transverse waves. Combining waves that propagate on orthogonal planes give rise to linear, elliptical, or spherical polarization, depending on their amplitudes and phase differences. Classical experiments of Huygens and Young demonstrated the principle of optical interference and diffraction. Generalization of Fraunhofer diffraction to scattering by a three-dimensional arrangement of atoms in crystals forms the basis of diffraction methods. Fresnel diffraction finds application in the design of zone plates for X-ray microscopy. Optical microscopy, with resolution given by the Rayleigh criterion to be approximately half the wavelength, works best when tailored to the optimal characteristics of the human eye (λ = 550 nm). Lenses suffer from spherical and chromatic aberrations, and astigmatism. Optical microscopes operate in bright-field, oblique, and dark-field imaging conditions, produce interference contrast, and can image with polarized light. Variants include confocal scanning optical microscopy (CSOM). Metallography, widely used to characterize microstructures, requires polished or chemically etched surfaces to provide optimal contrast. Finally, the polarization state of light reflected from the surface of a specimen is utilized in ellipsometry to obtain details of the optical properties and thickness of thin film materials.

Simulation of Electromagnetic Field Distribution at a Nanowire Probe for Near Field Scanning Optical Microscopy

2008 ◽  
Author(s):  
Nathan P. Malcolm ◽  
Alex J. Heltzel ◽  
Li Shi ◽  
John R. Howell
Keyword(s):  
Optical Microscopy ◽  
Signal To Noise Ratio ◽  
Near Field ◽  
Three Dimensional ◽  
Field Enhancement ◽  
Fdtd Simulation ◽  
Plasmonic Nanoparticle ◽  
Excitation Laser ◽  
Scanning Optical Microscopy ◽  
Near Field Scanning

This work studies a new design of a near field scanning optical microscopy (NSOM) probe based on a ZnO nanowire sub-wavelength waveguide terminated with a plasmonic gold nanoparticle. Three-dimensional finite difference time domain (FDTD) simulation is used to visualize light guiding in the nanowire and near field coupling between the plasmonic nanoparticle and the substrate. The simulation results reveal local field enhancement at the gap between the nanoparticle and a gold substrate when the nanowire axis is tilted from the substrate normal by a small angle. The enhancement occurs only along the cross section plane that is parallel to the polarization of the excitation laser beam. The regime of field enhancement is much smaller than the diameter of the 100 nm plasmonic particle, making the nanowire probe well suited for NSOM with superior spatial resolution and signal to noise ratio compared to the state of the art.

Confocal scanning optical microscopy and three-dimensional imaging

1992 ◽  
Vol 76 (1) ◽  
pp. 113-124 ◽  
Author(s):  
Michel Laurent ◽  
Georges Johannin ◽  
Hervé Guyader ◽  
Anne Fleury
Keyword(s):  
Optical Microscopy ◽  
Three Dimensional ◽  
Three Dimensional Imaging ◽  
Confocal Scanning ◽  
Scanning Optical Microscopy

Confocal scanning optical microscopy and its applications for biological specimens

1989 ◽  
Vol 94 (2) ◽  
pp. 175-206
Author(s):  
DAVID M. SHOTTON
Keyword(s):  
Optical Microscopy ◽  
Laser Scanning ◽  
Incident Light ◽  
Three Dimensional ◽  
Fluorescence Emission ◽  
Image Plane ◽  
Confocal Imaging ◽  
Two Dimensional Image ◽  
Confocal Scanning ◽  
Scanning Optical Microscopy

Confocal scanning optical microscopy (CSOM) is a new optical microscopic technique, which offers significant advantages over conventional microscopy. In laser scanning optical microscopy (SOM), the specimen is scanned by a diffractionlimited spot of laser light, and light transmitted or reflected by the in-focus illuminated volume element (voxel) of the specimen, or the fluorescence emission excited within it by the incident light, is focused onto a photodetector. As the illuminating spot is scanned over the specimen, the electrical output from this detector is displayed at the appropriate spatial position on a TV monitor, thus building up a two-dimensional image. In the confocal mode, an aperture, usually slightly smaller in diameter than the Airy disc image, is positioned in the image plane in front of the detector, at a position confocal with the in-focus voxel. Light emanating from this in-focus voxel thus passes through the aperture to the detector, while that from any region above or below the focal plane is defocused at the aperture plane and is thus largely prevented from reaching the detector, contributing essentially nothing to the confocal image. It is this ability to reduce out-of-focus blur, and thus permit accurate non-invasive optical sectioning, that makes confocal scanning microscopy so well suited for the imaging and three-dimensional tomography of stained biological specimens. In this review, I explain the principles of scanning optical microscopy and blur-free confocal imaging, discuss the various imaging modes of confocal microscopy, and illustrate some of its early applications.

scholarly journals Removing optical artifacts in near-field scanning optical microscopy by using a three-dimensional scanning mode

1999 ◽  
Vol 86 (5) ◽  
pp. 2785-2789 ◽  
Author(s):  
Claire E. Jordan ◽  
Stephan J. Stranick ◽  
Lee J. Richter ◽  
Richard R. Cavanagh
Keyword(s):  
Optical Microscopy ◽  
Near Field ◽  
Three Dimensional ◽  
Scanning Optical Microscopy ◽  
Near Field Scanning

Three-dimensional reconstruction of Paramecium primaurelia oral apparatus through confocal laser scanning optical microscopy

1992 ◽  
Vol 23 (4) ◽  
pp. 403-412 ◽  
Author(s):  
Francesco Beltrame ◽  
Paola Ramoino ◽  
Marco Fato ◽  
Maria Umberta Delmonte Corrado ◽  
Giampiero Marcenaro ◽  
...  
Keyword(s):  
Optical Microscopy ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Confocal Laser Scanning ◽  
Confocal Laser ◽  
Three Dimensional Reconstruction ◽  
Dimensional Reconstruction ◽  
Scanning Optical Microscopy
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