Thomas R. Ohnstein

Factors enhancing the reliability of touch-mode electrostatic actuators

This paper discusses the failure modes frequently encountered in touch-mode electrostatic actuators (TMEA) and reports on practical ways of increasing the time to failure. Humidity is identified as the main source of anomalies in the behavior of TMEA and charge trapping in the dielectric as the main cause of stiction. A method for direct charge measurement is derived and the measurements show good agreement with the calculated data. A new driving scheme is proposed that, together with surface treatments based on self-assembled monolayer, desensitizes the actuator to environmental conditions. In this way, actuators working without failure in room air for over 40 million cycles were obtained.

Electromagnetic linear actuators with inductive position sensing

Abstract Magnetically driven linear micro-actuators with 1 mN output force and hundreds of microns of total travel have been realized using LIGA-like processing techniques. These devices are driven at resonance frequencies of around 350 Hz and exhibit quality factors of about 300 in air. Exploiting wire-wound electromagnets, 300 μm resonant displacements have been demonstrated with drive signal currents of about 1 mA and power dissipation of less than 200 μW. In addition, the self inductance of the coils in these actuators varies linearly with plunger displacement. The inductance changes of about 1 μH μm −1 may be used for inductive position sensing and as a measure of output force.

YBa/sub 2/Cu/sub 3/O/sub 7/ superconductor microbolometer arrays fabricated by silicon micromachining

Linear arrays of YBa/sub 2/Cu/sub 3/O/sub 7/ transition edge microbolometers have been fabricated on silicon substrates using silicon micromachining to produce microbolometer structures with good thermal isolation. These bolometers, which are 85 mu m*115 mu m*1 mu m, have a noise equivalent power (NEP) of 9*10/sup -13/ W/Hz/sup 1/2/. (neglecting contact noise) and a thermal time constant of 24 ms. With contact noise, the NEP is 9*10/sup -12/ W/Hz/sup 1/2/. This performance indicates that a 2-D staring focal plane array of superconductor microbolometers could have a performance comparable to that of HgCdTe staring arrays without further improvements in the sharpness of the superconducting transition or reductions in the YBa/sub 2/Cu/sub 3/O/sub 7/ electrical noise. The use of silicon processing technology to fabricate the superconductor microbolometers results in a significant cost advantage over HgCdTe, and there is no long wavelength cutoff dependence in the sensitivity of a superconductor microbolometer.<<ETX>>

Ball-grid array architecture for microfabricated ion traps

State-of-the-art microfabricated ion traps for quantum information research are approaching nearly one hundred control electrodes. We report here on the development and testing of a new architecture for microfabricated ion traps, built around ball-grid array (BGA) connections, that is suitable for increasingly complex trap designs. In the BGA trap, through-substrate vias bring electrical signals from the back side of the trap die to the surface trap structure on the top side. Gold-ball bump bonds connect the back side of the trap die to an interposer for signal routing from the carrier. Trench capacitors fabricated into the trap die replace area-intensive surface or edge capacitors. Wirebonds in the BGA architecture are moved to the interposer. These last two features allow the trap die to be reduced to only the area required to produce trapping fields. The smaller trap dimensions allow tight focusing of an addressing laser beam for fast single-qubit rotations. Performance of the BGA trap as characterized with

OPTICAL PERFORMANCE OF HIGH-ASPECT LIGA GRATINGS II

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Resonator fiber optic gyro progress including observation of navigation grade angle random walk

Ca

LIGA tunable spectral filter performance

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Optical performance of high aspect LIGA gratings

ions is comparable to previous surface-electrode traps in terms of ion heating rate, mode frequency stability, and storage lifetime. We demonstrate two-qubit entanglement operations with

YBa2Cu307 superconducting microbolometer linear arrays

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Microstructure gas valve control

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