Publications

The modeling and validation of a 33 GHz shaped dielectric antenna design is investigated. The electromagnetic modeling was performed in both WIPL-D and FEKO, and was used to validate the antenna design prior to fabrication of the lens. It is shown that both WIPL-D and FEKO yield similarly accurate results...

A flow-injection analysis tandem mass spectrometry (FIA MSMS) method was developed for rapid quantitative analysis of 10 different inorganic and organic explosives. Performance is optimized by tailoring the ionization method (APCI/ESI), de-clustering potentials, and collision energies for each specific analyte. In doing so, a single instrument can be used to...

Nanofluidic channels are of great interest for DNA sequencing, chromatography, and drug delivery. However, metrology of embedded or sealed nanochannels and measurement of their fill-state have remained extremely challenging. Existing techniques have been restricted to optical microscopy, which suffers from insufficient resolution, or scanning electron microscopy, which cannot measure sealed...

Suspensions of plasmonic nanoparticles can diffract optical beams due to the combination of thermal lensing and self-phase modulation. Here, we demonstrate extremely efficient optical continuous wave (CW) beam switching across the visible range in optimized suspensions of 5-nm Au and Ag nanoparticles in non-polar solvents, such as hexane and decane...

We report the design, modelling, and proof-of-concept demonstration of a continuously fed, atmospheric-pressure microplasma metal sputterer that is capable of printing conductive lines narrower than the width of the target without the need for post-processing or lithographic patterning. Ion drag-induced focusing is harnessed to print narrow lines; the focusing mechanism...

Over the past 20 years, we have developed arrays of custom-fabricated silicon and InP Geiger-mode avalanche photodiode arrays, CMOS readout circuits to digitally count or time stamp single-photon detection events, and techniques to integrate these two components to make back-illuminated solid-state image sensors for lidar, optical communications, and passive imaging...

Sophisticated improvised explosive devices (IEDs) challenge the capabilities of current sensors, particularly in areas away from static checkpoints. This security gap could be filled by standoff chemical sensors that detect IEDs based on external trace explosive residues. Unfortunately, previous efforts have not led to widely deployed capabilities. Crucially, the physical...

The quality of epitaxial layers in quantum cascade lasers (QCLs) has a primary impact on QCL performance, and establishing correlations between epitaxial growth and materials properties is of critical importance for continuing improvements. We present an overview of the growth challenges of these complex QCL structures; describe the metalorganic vapor...

Pump-limited kW-class operation in a multimode fiber amplifier using adaptive mode control and a photonic lantern front end was achieved. An array of three single-mode fiber inputs was used to adaptively inject the appropriate superposition of input modes in a three-mode gain fiber to achieve the desired mode at the...

This Work-In-Progress paper details the process and lessons learned when converting a hands-on engineering minicourse to a scalable, self-paced Massively Open Online Course (MOOC). Online courseware has been part of academic and industry training and learning for decades. Learning activities in online courses strive to mimic in-person delivery by including...