Versatile three-dimensional cryogenic micropositioning device

Abstract

A simple design for a mechanically driven three-dimensional cryogenic micropositioner is presented. The design is based on a parallelogram structure constructed from leaf springs and wires. Actuation is achieved by the elastic deformation of the parallelogram by screws. Positions within a volume of roughly (2 mm)3 are attainable. The precision and reproducibility of positioning are in the μm-range. The deviations from linearity are smaller than 10% for the whole working range and the deviation from orthogonality is smaller than 3°. Calibration measurements performed on a Cu-mesh with a lattice constant of 60 μm are presented. In an experiment investigating the ballistic transport of carriers in the semimetal Bi, two such devices are used. The first one is used as a scanning unit for an optical fiber and the second one is used as micropositioner for a Cu point contact.

Development of a middle-range six-degrees-of-freedom system

“…The prototype unit had a deflection sensitivity of 0.3 mm/V and travelled a distance of -60 mm. Heil et al [2] designed a three-dimensional cryogenic micropositioner which was based on a parallelogram structure that was constructed from leaf springs and wires. The actuation was achieved by the elastic deformation of the parallelogram using screws.…”

A high resolution long travel friction-drive micropositioner with programmable step size

“…11 Another design, a bimorph-driven X -Y -Z translation stage 12 achieved the sensitivity of deformation of 0.3 m/V and the moving range was 660 m. The design of using leaf springs was found in a three-dimensional ͑3D͒ microposition mechanism. 13 Scott-Russel linkage was integrated in a linear micropositioner 14 and achieved resolution of 40 nm with a travel of greater than 100 m. A piezoelectric driven precision XY z microposition mechanism 15 achieved the displacement sensitivity of 0.12 m/V with 10 nm resolution in the X and Y axes, 4.2 rad/V with 0.15 rad resolution in the z axis and interaction between axes was within 1.2%.…”

Imaging of Longitudinal Electron Focusing by Light-Induced Carrier Excitation

“…One PC (emitter) was used to inject carriers into the crystal and the other PC (collector) detected the collector voltage V c . For certain values of a longitudinal magnetic field B l (along the line connecting emitter and collector, Sharvin geometry) he observed peaks in V c , a phenomenon which he called longitudinal electron focusing.We recently presented a new experimental technique which allows one to image the far field radiation pattern of a carrier point source [3][4][5][6]. The real space imaging capability makes this technique the ideal tool for studies of the spatial distribution of the trajectories of carriers under the influence of a magnetic field, for example in the Sharvin geometry.…”

“…We recently presented a new experimental technique which allows one to image the far field radiation pattern of a carrier point source [3][4][5][6]. The real space imaging capability makes this technique the ideal tool for studies of the spatial distribution of the trajectories of carriers under the influence of a magnetic field, for example in the Sharvin geometry.…”

“…1(a) is similar to the one described in [3,6]. The beam of a 30 mW Ar laser is coupled into an optical fiber which illuminates a small spot of the surface of a Bi single crystal slab of thickness d ഠ l ‫ء‬ .…”