Typical measurements of light in the near-field utilize a photodetector such as a photomultiplier... more Typical measurements of light in the near-field utilize a photodetector such as a photomultiplier tube or a photodiode, which is placed remotely from the region under test. This kind of detection has many draw-backs including the necessity to detect light in the far-field, the influence of background propagating radiation, the relatively narrowband operation of photodetectors which complicates the operation over a wide wavelength range, and the difficulty in detecting radiation in the far-IR and THz. Here we review an alternative near-field light measurement technique based on the detection of optically induced forces acting on the scanning probe. This type of detection overcomes some of the above limitations, permitting true broad-band detection of light directly in the near-field with a single detector. The physical origins and the main characteristics of optical force detection are reviewed. In addition, intrinsic effects of the inherent optical forces for certain operation modal...
We present an analytical model able to explain the optical signal recorded during our experimenta... more We present an analytical model able to explain the optical signal recorded during our experimental approach curves in the infrared at a wavelength lambda=10.6 microm, with a home-made apertureless near-field scanning optical microscope ANSOM. This model uses classical electrodynamics to calculate the scattering cross section of the oscillating tip, considered as a dipole, and its dielectric image in the sample as a function of the tip-sample separation from the near-field to the far-field regime. The dipoles are placed in a non-uniform electric field because of the standing wave arising from the interference between the incident and the specular laser beams. We also added a background field coming from a scatterer on the surface in order to account for zeroing of the optical signal for particular tip-sample separation and interference patterns.
The superconducting heavy fermion system UPt3 has been studied by means of point contacts adjuste... more The superconducting heavy fermion system UPt3 has been studied by means of point contacts adjusted with a bimorph stepping motor working in the mixing chamber of a dilution refrigerator (T >= 30 mK). The measured differential resistance curves of Ag/UPt3 point contacts are compared with the usual isotropic BTK model describing the Andreev-reflection process of quasiparticles in normal/superconductor point contacts.
Typical measurements of light in the near-field utilize a photodetector such as a photomultiplier... more Typical measurements of light in the near-field utilize a photodetector such as a photomultiplier tube or a photodiode, which is placed remotely from the region under test. This kind of detection has many draw-backs including the necessity to detect light in the far-field, the influence of background propagating radiation, the relatively narrowband operation of photodetectors which complicates the operation over a wide wavelength range, and the difficulty in detecting radiation in the far-IR and THz. Here we review an alternative near-field light measurement technique based on the detection of optically induced forces acting on the scanning probe. This type of detection overcomes some of the above limitations, permitting true broad-band detection of light directly in the near-field with a single detector. The physical origins and the main characteristics of optical force detection are reviewed. In addition, intrinsic effects of the inherent optical forces for certain operation modal...
We present an analytical model able to explain the optical signal recorded during our experimenta... more We present an analytical model able to explain the optical signal recorded during our experimental approach curves in the infrared at a wavelength lambda=10.6 microm, with a home-made apertureless near-field scanning optical microscope ANSOM. This model uses classical electrodynamics to calculate the scattering cross section of the oscillating tip, considered as a dipole, and its dielectric image in the sample as a function of the tip-sample separation from the near-field to the far-field regime. The dipoles are placed in a non-uniform electric field because of the standing wave arising from the interference between the incident and the specular laser beams. We also added a background field coming from a scatterer on the surface in order to account for zeroing of the optical signal for particular tip-sample separation and interference patterns.
The superconducting heavy fermion system UPt3 has been studied by means of point contacts adjuste... more The superconducting heavy fermion system UPt3 has been studied by means of point contacts adjusted with a bimorph stepping motor working in the mixing chamber of a dilution refrigerator (T >= 30 mK). The measured differential resistance curves of Ag/UPt3 point contacts are compared with the usual isotropic BTK model describing the Andreev-reflection process of quasiparticles in normal/superconductor point contacts.
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Papers by Yannick Wilde