Publications
Analog coupled oscillator based weighted Ising machine
Summary
Summary
We report on an analog computing system with coupled non-linear oscillators which is capable of solving complex combinatorial optimization problems using the weighted Ising model. The circuit is composed of a fully-connected 4-node LC oscillator network with low-cost electronic components and compatible with traditional integrated circuit technologies. We present the...
Valleytronics: opportunities, challenges, and paths forward
Summary
Summary
A lack of inversion symmetry coupled with the presence of time-reversal symmetry endows 2D transition metal dichalcogenides with individually addressable valleys in momentum space at the K and K' points in the first Brillouin zone. This valley addressability opens up the possibility of using the momentum state of electrons, holes...
Highly Efficient All-Optical Beam Modulation Utilizing Thermo-optic Effects
Summary
Summary
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...
MOVPE growth of LWIR AlInAs/GaInAs/InP quantum cascade lasers: impact of growth and material quality on laser performance
Summary
Summary
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...
Bringing physical construction and real-world data collection into a massively open online course (MOOC)
Summary
Summary
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...
A fully integrated broadband sub-mmWave chip-to-chip interconnect
Summary
Summary
A new type of broadband link enabling extremely high-speed chip-to-chip communication is presented. The link is composed of fully integrated sub-mmWave on-chip traveling wave power couplers and a low-cost planar dielectric waveguide. This structure is based on a differentially driven half-mode substrate integrated waveguide supporting the first higher order hybrid...
Effect of surface roughness and H-termination chemistry on diamond's semiconducting surface conductance
Summary
Summary
The H-terminated surface of diamond when activated with NO2 produces a surface conduction layer that has been used to make FETs. Variations in processing can significantly affect this conduction layer. This article discusses the effect of diamond surface preparation and H termination procedures on surface conduction. Surface preparations that generate...
Four-tap RF canceller evaluation for indoor in-band full-duplex wireless operation
Summary
Summary
Analog self-interference mitigation techniques are currently being investigated in a variety of operational settings for In-Band Full-Duplex (IBFD) systems. The significant multipath effects of realistic environments, such as inside buildings, can severely limit performance. The influence of different transceiver parameters on the effectiveness of a four-tap RF canceller using a...
Covariance estimation in terms of Stokes parameters with application to vector sensor imaging
Summary
Summary
Vector sensor imaging presents a challenging problem in covariance estimation when allowing arbitrarily polarized sources. We propose a Stokes parameter representation of the source covariance matrix which is both qualitatively and computationally convenient. Using this formulation, we adapt the proximal gradient and expectation maximization (EM) algorithms and apply them in...
Nonlinear equalization of microwave photonic links
Summary
Summary
High dynamic range is a key requirement in advanced microwave photonic systems. We demonstrate compensation of nonlinearities occurring in microwave photonic links using a novel digital nonlinear equalization technique and demonstrate suppression of distortion products by 33 dB with a small number of equalizer coefficients.