MNTL Hilights report web (Apr. 2016) - Page 14

CHIP-SCALE HYBRID MICROSYSTEMS FOR RF COMMUNICATION, SENSING, AND IMAGING APPLICATIONS ECE Assistant Professor Songbin Gong has demonstrated a new type of multi-frequency RF filter based on two-port laterally vibrating lithium niobate MEMS resonators. The new filter, which operates on most broadband radio and tv, cellphone, and Wi-Fi signals, exhibits electromechanical coupling coefficients of 8% at 500 MHz and 14.6% at 750 MHz, enabling low loss and wideband filtering. This filter may provide a viable path to implement chip-scale reconfigurable front-ends, which includes all the components in the receiver that process the signal at the original incoming radio frequency—a solution desired by the telecommunications industry. PROVIDING A BETTER UNDERSTANDING OF TOPOLOGICAL INSULATORS ECE Associate Professor Matthew Gilbert and Physics faculty colleague Nadya Mason are investigating novel materials called topological insulators and how they differ from traditional semiconducting materials—an important step toward post-CMOS applications. Topological insulators have insulating interiors but surfaces that allow for the flow of electrons. They have far different physical qualities than standard semiconducting materials like silicon. Their research focuses on conductance oscillations in nanowires made of the topological insulator Bi2Se3, demonstrating that conduction occurs only on the surface, which may eliminate the resistivity and related power dissipation due to bulk scattering that occurs in typical device materials such as copper and silicon. In addition, they found conductance behavior consistent with a “topological mode” that can be turned on and off with a magnetic field. This unique topological mode is a necessary component of proposed fault-tolerant quantum computing using these materials, yet has not previously been demonstrated in nanowires. BRIGHTNESS EQUALIZED QUANTUM DOTS IMPROVE BIOLOGICAL IMAGING Bioengineering Assistant Professor Andrew Smith has introduced a new class of light-emitting quantum dots (QDs) with tunable and equalized fluorescence brightness across a broad range of colors. This results in more accurate measurements of molecules in diseased tissue and improved quantitative imaging capabilities. “Previously light emission had an unknown correspondence with molecule number,” explained Smith. “Now it can be precisely tuned and calibrated to accurately count specific molecules. This will be particularly useful for understanding complex processes in neurons and cancer cells to help us unravel disease mechanisms, and for characterizing cells from diseased tissue of patients.” According to the researchers, these new materials will be especially important for imaging in complex tissues and living organisms where there is a major need for quantitative imaging tools that can provide a consistent and tunable number of photons per tagged biomolecule. They are also expected to be used for precise color matching in light-emitting devices and displays, and for photon-on-demand encryption applications. The same principles should be applicable across a wide range of semiconducting materials. 14