Operating in dynamic lighting conditions and in greatly varying backgrounds is challenging. Current paints and state-ofthe-
art passive adaptive coatings (e.g. photochromics) are not suitable for multi- environment situations. A semi-active,
low power, skin is needed that can adapt its reflective properties based on the background environment to minimize
contrast through the development and incorporation of suitable pigment materials. Electrofluidic skins are a reflective
display technology for electronic ink and paper applications. The technology is similar to that in E Ink but makes use of
MEMS based microfluidic structures, instead of simple black and white ink microcapsules dispersed in clear oil.
Electrofluidic skin's low power operation and fast switching speeds (~20 ms) are an improvement over current state-ofthe-
art contrast management technologies. We report on a microfluidic display which utilizes diffuse pigment dispersion
inks to change the contrast of the underlying substrate from 5.8% to 100%. Voltage is applied and an electromechanical
pressure is used to pull a pigment dispersion based ink from a hydrophobic coated reservoir into a hydrophobic coated
surface channel. When no voltage is applied, the Young-Laplace pressure pushes the pigment dispersion ink back down
into the reservoir. This allows the pixel to switch from the on and off state by balancing the two pressures. Taking a
systems engineering approach from the beginning of development has enabled the technology to be integrated into larger
A new approach for microelectromechanical systems (MEMS) hydrophones is discussed, which yields miniature, low
power, and high performance hydrophones. The prototype devices use a laser interferometer with integrated low power
electronics built on conventional silicon on sapphire (SOS) complimentary metal oxide semiconductor (CMOS)
technology to optically detect pressure waves. Results show sensitivities of -143 dBV re 1 μPa, comparable to or better
than piezoelectric, capacitive condenser, or other optical approaches. The implication is to make very low cost
hydrophones while drastically reducing the power and computational requirements. This is viewed as a disruptive
technology for areas such as coastal defense and port security where cost, size and power consumption is key.
MEMX Corporation in collaboration with Johns Hopkins University Applied Physics Laboratory (JHU/APL) has developed micro-mirror technology applicable to free-space multi-access optical communications terminals. Based on their previously developed micro-electro-mechanical systems (MEMS) optical switches, these new units are being evaluated for applications on spacecraft. These devices must operate within very accurate digitally-controlled pointing and tracking subsystems, which are an essential adjunct to the long-haul optical communication channels that would be operated potentially from geosynchronous earth orbit (GEO) to ground. For such spacecraft applications high-powered laser diodes are likely be the required transmitter. Coupled with their potential operation in a vacuum or at partial atmospheric pressures, MEMS mirror shape stability and fabrication tolerances are of key concern to a system designer. To this end we have measured the performance of preliminary micro-mirror units in terms of angular jitter, focal spot stability, and open and closed-loop response versus laser transmitter power in both ambient air and at low partial pressures. We will describe the fabrication process as well as the experimental test configurations and results in the context of optical beamsteering. We will also discuss the applicability and scalability of this technology to multi-access terminals.