Publications

We report on the development of sub-millimeter size adaptive liquid microlenses and microlens arrays using two immiscible liquids to form individual lenses. Microlenses and microlens arrays having aperture diameters as small as 50 microns were fabricated on a planar quartz substrate using patterned hydrophobic/hydrophilic regions. Liquid lenses were formed by...

The authors report on the development of surfaces containing artificially fabricated structures of dual nanometer and micrometer surfaces that allow an aqueous droplet to be reversibly switched by electrowetting from a Cassie state with low adhesion to a Wenzel state with high adhesion. A variety of geometries were fabricated to...

We present a method of photoacoustic spectroscopy in which a laser beam tuned to an absorption feature of a gas is swept through its plume at the speed of sound. The resulting coherent addition of acoustic waves leads to an amplification of the signal without the need for a resonant...

The ability to reversibly switch between a hydrophobic Cassie state and a hydrophilic Wenzel state is often not possible on textured surfaces because of energy barriers which result from the geometry of the microstructure. In this paper, we report on a simple microstructure geometry that allows an aqueous droplet to...

We present an approach for rational design and optimization of plasmonic arrays for ultrasensitive surface enhanced infrared absorption (SEIRA) spectroscopy of specific protein analytes. Motivated by our previous work that demonstrated sub-attomole detection of surface-bound silk fibroin [Proc. Natl. Acad. Sci. U.S.A. 106, 19227 (2009)], we introduce here a general...

We have investigated the driven dynamics of a superconducting flux qubit that is tunably coupled to a microwave resonator. We find that the qubit experiences an oscillating field mediated by off-resonant driving of the resonator, leading to strong modifications of the qubit Rabi frequency. This opens an additional noise channel...

Accurate conversion of wideband multi-GHz analog signals into the digital domain has long been a target of analog-to-digital converter (ADC) developers, driven by applications in radar systems, software radio, medical imaging, and communication systems. Aperture jitter has been a major bottleneck on the way towards higher speeds and better accuracy...

We have developed a remote detection system consisting of commercially available retroreflective material coated with an analyte-specific colorimetric dye. Quantitative performance modeling predicts that, given the appropriate indicator dye, a system with a 10 cm optic and eye-safe illumination should be capable of detecting small droplets of contamination at kilometer...

High-sensitivity (ng/cm2) optical detection of the explosive 2,4,6- trinitrotoluene (TNT) is demonstrated using photodissociation followed by laser-induced fluorescence (PD-LIF). Detection occurs rapidly, within 6 laser pulses (~7 ns each) at a range of 15 cm. Dropcasting is used to create calibrated samples covering a wide range of TNT concentrations; and...

Our recent work has showed that diffractively coupled nanoplasmonic arrays for Fourier transform infrared (FTIR) microspectroscopy can enhance the Amide I protein vibrational stretch by up to 105 times as compared to plain substrates. In this work we consider computationally the impact of a microscope objective illumination cone on array...