High Spatial Resolution Imaging with Near-Field Scanning Optical Microscopy in Liquids

The diffraction of visible light limits the spatial resolution in conventional optical microscopy to about 200-300 nm. In near-field scanning optical microscopy (NSOM), resolution is improved by bringing the light source, such as the end of an optical fiber, very close to the sample surface. Laser light coupled into the opposite end of the fiber propagates down the fiber core and is emitted from the aperture of the tip. When the sample is in the near-field(roughly within one tip diameter of the end of the tip), the spatial resolution is essentially equal to the diameter of the aperture at the end of the tip and is not determined by diffraction effects. Two-dimensional imaging is accomplished by raster-scanning the sample underneath the fiber tip and collecting transmitted or reflected light at a photodetector.

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Super-resolution imaging with near-field scanning optical microscopy (NSOM)

Ultramicroscopy ◽

10.1016/0304-3991(88)90223-9 ◽

1988 ◽

Vol 25 (2) ◽

pp. 155-163 ◽

Cited By ~ 20

Author(s):

E. Betzig ◽

M. Isaacson ◽

H. Barshatzky ◽

A. Lewis ◽

K. Lin

Keyword(s):

Optical Microscopy ◽

Near Field ◽

Super Resolution ◽

Resolution Imaging ◽

Scanning Optical Microscopy ◽

Near Field Scanning

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Photoreflectance Near-Field Scanning Optical Microscopy

MRS Proceedings ◽

10.1557/proc-588-13 ◽

1999 ◽

Vol 588 ◽

Cited By ~ 1

Author(s):

Charles Paulson ◽

Brian Hawkins ◽

Jingxi Sun ◽

Arthur B. Ellis ◽

Leon Mccaughan ◽

...

Keyword(s):

Optical Microscopy ◽

Electric Fields ◽

Spatial Resolution ◽

High Intensity ◽

Near Field ◽

And Topology ◽

Wavelength Resolution ◽

Scanning Optical Microscopy ◽

Near Field Scanning ◽

Sub Wavelength

AbstractA novel Near-field Scanning Optical Microscopy (NSOM) technique is used to obtain simultaneous topology, photoluminescence and photoreflectance (PR) spectra. PR spectra from GaAs surfaces were obtained and the local electric fields were calculated. Sub-wavelength resolution is expected for this technique and achieved for PL and topology measurements. Photovoltages, resulting from the high intensity of light at the NSOM tip, can limit the spatial resolution of the electric field determination.

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Surface photoelectrochemistry using near-field scanning optical microscopy (NSOM)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100166750 ◽

1996 ◽

Vol 54 ◽

pp. 858-859

Author(s):

Patrick J. Moyer

Keyword(s):

Optical Microscopy ◽

Spatial Resolution ◽

Shear Force ◽

Force Feedback ◽

Near Field ◽

Feedback Mechanism ◽

Frequency Spectra ◽

Water Resonance ◽

Scanning Optical Microscopy ◽

Near Field Scanning

Near-field scanning optical microscopy (NSOM) has been used to characterize and modify surfaces with lateral spatial resolution as high as 50 nm. Some of these experiments were performed under electrochemical conditions. Progress towards this goal involved several important steps. They include proving adequate operation of the shear force feedback mechanism in liquids and fabrication of appropriate NSOM fiber probes.With regards to shear force feedback, which is used to maintain the fiber probe within the near field of the sample, there has been ample discussion regarding the physics of the tip-sample interaction. It is important for biological and photoelectrochemical applications that the feedback mechanism operates successfully in liquid environments. Our results indicate that shear force operation in water allows for high spatial resolution NSOM characterization while providing high force sensitivity. When comparing the frequency spectra of the probe resonances in air and water, the water resonance is broadened. The broadened resonance peak when completely immersing the probe in water indicates an increase in damping.

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Prospects for Molecular Spectroscopy at High Spatial Resolution

Zeitschrift für Physikalische Chemie ◽

10.1524/zpch.2001.215.8.1025 ◽

2001 ◽

Vol 215 (8) ◽

Cited By ~ 3

Author(s):

F. Hamann

Keyword(s):

Spatial Resolution ◽

Single Molecule ◽

High Spatial Resolution ◽

Molecular Spectroscopy ◽

Near Field ◽

Dark Field ◽

Optical Methods ◽

Weak Scattering ◽

Scanning Optical Microscopy ◽

Near Field Scanning

This work discusses the prospects and feasibility of optical spectroscopy and microscopy of single molecules at nanometer resolution via apertureless, antenna-based near-field scanning optical microscopy. First, different near-field optical methods are compared, which detect the weak scattering or fluorescence from a probe–single molecule interaction at high spatial resolution. Specifically, ultimate sensitivities of coherent (bright-field) and non-coherent (dark-field) apertureless near-field microscopes for resonant (e.g., scattering, absorption) and non-resonant (e.g.,

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