Papers by Author: David Wood

Abstract: Here we present results from key aspects of our interest in using micromachined devices in the THz region. First, our early work on making filters from rods of gold-coated SU8 is described. Pass (up to 97%) and stop bands can be observed which are theoretically underpinned by both FDTD and complex band structure simulations. Second, there is a discussion of how THz radiation passes through two-dimensional periodic arrays of subwavelength apertures. In particular, the geometry of the arrays has been studied with time-domain spectroscopy. A time-of-flight model is presented which can be used to provide insight into the operation of these arrays and has implications for the optimum design of THz plasmonic sensors. Finally, we report the THz ‘super’ extraordinary transmission properties of an optimised hybrid subwavelength aperture array, surrounded by subwavelength grooves.

Abstract: In this work, we present the characterisation of an electrothermally actuated microgripper that operates in both dry and liquid media, and shows improved performance versus existing devices. The microgripper, fabricated in a combination of polymeric (SU8) and conductive materials (Au), is able to produce displacements up to 110 μm in air and 30 μm in liquid. In both cases, the voltage and the electrical power required is minimal (less than 3 V and 180 mW respectively) and so both, high temperatures and electrolysis, are prevented. Micromanipulation experiments have successfully demonstrated the gripping, holding and transport of mice oocytes (approx. diameter 100 μm) in a biological media.