Harry Shaw

Nanotube, nanowire, and nanocircuit behavior in simulated space environments

This paper reports the results of two separate heavy ion irradiation experiments. In the first set, nanomaterial samples including single and multi wall carbon nanotubes and electrospun carbon nanofibers, with well-graphitized vapor grown carbon fibers as controls, were irradiated using a primary beam of Krypton-86 ions at 142 Amp MeV. The single and multi wall carbon nanotube samples sustained little damage from the highest radiation dose. In the second set, a gallium nitride nanowire-based field effect transistor was irradiated using a primary beam of Krypton-78 ions at 140 Amp MeV. The nanocircuit maintained normal function under high active bias and high radiation dose. Krypton-86 and Krypton-78 are representative of high-Z heavy ions encountered in a space radiation environment. Results from the pre-irradiation structure and optoelectronic characterization of the gallium nitride nanowires are also reported.

NASA Electronic Parts and Packaging (NEPP) Program: assurance research on optoelectronics

The wide variety of optoelectronics applications in NASA flight systems and instruments require that optoelectronic technologies meet the demanding requirements of the space environment throughout mission life. These requirements vary widely from intense radiation near Jupiter to the very cold temperatures on the Martian surface to the effects of solar flares in Earth orbit. Considerable work has been performed under the NEPP Program to meet these assurance needs and minimize the risk of insertion of optoelectronics in NASA systems. In this paper we provide recent examples of this work for a variety of NASA mission applications that employ various optoelectronic devices.

Transparent reflectarray antenna printed on solar cells

This paper presents an integrating of highly transparent X band reflectarray on the cover glass of solar panels. Two types of element geometries are studied, and optimal unit cell element, effect of the solar cell on the antenna, feed consideration, and final design data are presented. The overall transparency and aperture efficiency of the design are more than 90% and 40% respectively, making it a promising solution as a high gain conformal satellite antenna.

Securing and auto-synchronizing communication over free-space optics using quantum key distribution and chaotic systems

Free-Space Optical (FSO) communication provides very large bandwidth, relatively low cost, low power, low mass of implementation, and improved security when compared to conventional Free-Space Radio-Frequency (FSRF) systems. In this paper, we demonstrate a communication protocol that demonstrates improved security and longer-range FSO communication, compared to existing FSO security techniques, such as N-slit interferometers. The protocol integrates chaotic communications with Quantum Key Distribution (QKD) techniques. A Lorenz chaotic system, which is inherently secure and auto-synchronized, is utilized for secure data communications over a classical channel, while QKD is used to exchange crucial chaotic system parameters over a secure quantum channel. We also provide a concept of operations for a NASA mission combining chaotic communications and QKD operating synergistically in an end-to-end space communications link. The experimental simulation results and analysis are favorable towards our approach.

Flying qubit investigations for heterostructure-based qubit implementations

Flying qubit designs have emerged as a new approach for adding dynamic control to solid-state qubit implementations including heterostructure-based electron gas implementations. The flying qubit approach utilizes the potential minimum of a SAW wave for the capture and transport of a single or few electron(s) from a reduced dimensionality electron pool. Many details of the interactions between the dynamic potential well induced by propagating SAW wave with the reduced dimensionality electron pool are unknown. In the present work, we investigate the effect of the SAW wave longitudinal component modelled as perturbation to the k-space momentum in the transport direction for a heterostructure-based finite width 1D channel. A new quadratic expression for the k-space momentum and a new expression for the number density are reported for the first time. A major effect of positive or negative longitudinal perturbations on electron transport is the introduction of shifts that can affect both quantum channel accessibility and number density allowed occupations.