Volume 83, Issue 3, 01 February 1998
Index of content:
- GENERAL PHYSICS: NUCLEAR, ATOMIC, AND MOLECULAR (PACS 01-39)
Observation of neutron guided waves from the open end of a thin film waveguide and a waveguide interferometry83(1998); http://dx.doi.org/10.1063/1.366810View Description Hide Description
Neutrons guided wave propagation were observed at the open end of a thin film waveguide. A low-index-leaky waveguide coupler is used for coupling the incident beam into the thin guiding film. After guided propagation over a distance of a few millimeters, the neutrons are diffracted at the open end of the guide giving a Fraunhofer diffraction pattern. The diffracted neutron intensity distribution is in fairly good agreement with the theory. An interferometer based on the splitting of the far-field pattern on two separate peaks is proposed.
83(1998); http://dx.doi.org/10.1063/1.366811View Description Hide Description
New piezoresistivesilicon cantilevers designed specifically for torque magnetometry on microscopic samples have been microfabricated and tested. These levers have been optimized to detect the torque in two directions corresponding to flexion and torsion. Torque resolution of can be achieved depending on the operating mode. In one version an integrated loop allows an absolute calibration of the device with an accuracy of 1%. This loop can also be used to excite the lever mechanically. One application is the determination of the mass of nanogram samples by measuring the resonance frequency shift (nanobalance).
Reflection-mode scanning near-field optical microscopy: Influence of sample type, tip shape, and polarization of light83(1998); http://dx.doi.org/10.1063/1.366812View Description Hide Description
A reflection-mode aperture-type scanning near-field optical microscope (R-SNOM) based on the external collection of the reflected light is presented. The light detection is based on an elliptical mirror setup, with the tip and sample at one focus, and a photomultiplier tube at the other. Results are presented on the general imaging properties of this microscope. The results presented concentrate on an analysis of the gap-width dependence of the optical signal, on resolution and on the contrast mechanisms which may be used in R-SNOM imaging, including reflectivity, polarization/magneto-optics, and topographic effects.
83(1998); http://dx.doi.org/10.1063/1.366813View Description Hide Description
The dielectric properties of fluorozirconate glassesdoped with different impurities have been investigated in the frequency region of 3.0–12.5 GHz using a microwave network analyzer. For glasses containing oxide impurities such as PbO, and the position of the dielectric resonance, which is observed in the pure fluoride glass, shifts to higher frequencies. Amplitudes of the resonance peaks also become much smaller. The oxide impurities are observed to exist as large numbers of tiny precipitates in the glasses. When the glasses are doped with the position of the resonance peak shifts to a higher frequency but the amplitude of the peak remains unchanged. The may be substituted for in the glasses. A higher half-resonance width is observed in the doped fluorozirconate glasses. The changes in the dielectric properties are attributed to the different behaviors of the impurities, which affect the structural interunit vibration in the fluoride glasses.