Microscope optique en champ proche

Near-field scanning optical microscopy (NSOM) or scanning near-field optical microscopy (SNOM) is a microscopy technique for nanostructure investigation that breaks the far field resolution limit by exploiting the properties of evanescent waves. In SNOM, the excitation laser light is focused through an aperture with a diameter smaller than the excitation wavelength, resulting in an evanescent field (or near-field) on the far side of the aperture. When the sample is scanned at a small distance below the aperture, the optical resolution of transmitted or reflected light is limited only by the diameter of the aperture. In particular, lateral resolution of 6 nm and vertical resolution of 2–5 nm have been demonstrated. As in optical microscopy, the contrast mechanism can be easily adapted to study different properties, such as refractive index, chemical structure and local stress. Dynamic properties can also be studied at a sub-wavelength scale using this technique. NSOM/SNOM is a form of scanning probe microscopy. Edward Hutchinson Synge is given credit for conceiving and developing the idea for an imaging instrument that would image by exciting and collecting diffraction in the near field. His original idea, proposed in 1928, was based upon the usage of intense nearly planar light from an arc under pressure behind a thin, opaque metal film with a small orifice of about 100 nm. The orifice was to remain within 100 nm of the surface, and information was to be collected by point-by-point scanning. He foresaw the illumination and the detector movement being the biggest technical difficulties. John A. O'Keefe also developed similar theories in 1956. He thought the moving of the pinhole or the detector when it is so close to the sample would be the most likely issue that could prevent the realization of such an instrument. It was Ash and Nicholls at University College London who, in 1972, first broke the Abbe’s diffraction limit using microwave radiation with a wavelength of 3 cm. A line grating was resolved with a resolution of λ0/60.

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Publications associées (45)

Chemically etched plastic optical fiber probe for near-field scanning optical microscopy in liquids

Giovanni Dietler, Anton Smirnov, Kanat Dukenbayev

Some preliminary results and experimental details of Near-field Scanning Optical Microscopy (NSOM) operation in liquids have been reported by us earlier(1-4). Here we present the first use of custom m

SPIE-INT SOC OPTICAL ENGINEERING2019

Scanning near-field optical microscopy with new probes and feedback modes

Anton Smirnov

Scanning Near-field Optical Microscopy (SNOM) technique enables to overcome Abbe diffraction limit of far-field optics as well as to obtain simultaneously optical and topographical images. While the o

EPFL2019

Long-life plastic optical fiber probes for scanning near-field optical microscope

Giovanni Dietler, Anton Smirnov, Ekaterina Rostova

Nowadays, sharpened glass fiber - made probes attached to a quartz tuning fork (TF) and exploiting the shear force - based feedback are by far the most popular in the field of SNOM. These probes are e

SPIE-INT SOC OPTICAL ENGINEERING2018

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Giovanni Dietler, Nicolas Grandjean, Klaus Kern, Mounir Driss Mensi, Vincenzo Savona, Hatice Altug, Toralf Scharf, Yves Bellouard, Giorgio Margaritondo, Dusan Vobornik

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