Tech Briefs

Burner Rig Testing of A500® C/SiC

There is growing interest in developing, testing, and deploying ceramic-matrix composites (CMCs) into commercial and military aerospace gas turbine engines due to their durability under extreme conditions and weight-savings potential. For military applications, the focus is on the afterburning section of the turbine engine, including the flameholder, augmentor liner, and both the convergent and divergent segments of the exhaust nozzle. These are demanding applications because of the high temperatures and rapid thermal cycles.

Posted in: Briefs, Aerospace, Composites, Materials, Instrumentation, Measuring Instruments, Monitoring, Test & Measurement

Space Debris Orbit and Attitude Prediction for Enhanced and Efficient Space Situational Awareness

This research deals with the problem of modelling the orbit and attitude motion of uncontrolled manmade objects in orbit about the Earth, which tumble due to the natural influences of the near-Earth space environment. A mathematical, physics-based and computational approach is taken to model the forces and torques that drive the orbit and attitude evolution of such objects. The main influence modelled is solar radiation pressure (SRP), which is the interaction of solar electromagnetic radiation with the surface of an object, leading to both forces and torques that influence the orbital and attitude motion. Other influences, such as the gravitational field of the Earth, are also modelled.

Posted in: Briefs, Aerospace, Imaging, Materials, Simulation Software, Transportation

Fundamental Aspects of Single Molecule and Zeptomole Electroanalysis

The objective of this research program was to provide the fundamental understanding required for using the principles of electroanalytical chemistry to detect target molecules at very low concentration, including single molecules, with high specificity, simplicity, and low power.

Posted in: Briefs, Aerospace, Defense, Materials, Nanotechnology, Inspection Equipment, Instrumentation, Measuring Instruments, Monitoring, Test & Measurement, Testing Procedures

Spatial Resolution and Contrast of a Focused Diffractive Plenoptic Camera

The concept of an imaging system that captures both spatial and spectral information has existed for a while. An example of one such imaging system that encodes both location and wavelength into an image is a Fourier Transform Spectrometer (FTS).

Posted in: Briefs, Aerospace, Cameras, Imaging, Optical Components, Optics

Integrated Magneto-Optical Devices for On-Chip Photonic Systems

The magneto-optical (MO) oxide layer consists of (Bi,Y)3Fe5O12 or BiYIG, bismuth garnet. This material was selected because it has a better figure of merit than the CeYIG previously used, especially at lower wavelengths (1310 nm vs. 1550 nm). A top-down deposition process was developed in which BiYIG/YIG stacks are grown on the Si waveguide with YIG on top. The stack is annealed at 800°C/5 min to crystallize both layers, with the YIG templating the BiYIG leading to garnet phases rather than other oxides, and the BiYIG is directly on the Si waveguide. Initial attempts led to a film with Bi oxide phases, because the Bi was in excess and could not escape during the anneal as occurs in Si/YIG/BiYIG stacks. Hence the composition was adjusted to include slightly more Fe, which yielded films with only garnet peaks.

Posted in: Briefs, Aeronautics, Aerospace, Aviation, Electronic Components, Electronics, Electronics & Computers, Manufacturing & Prototyping, Materials, Optical Components, Optics, Photonics, Semiconductors & ICs

Low Power Optical Phase Array Using Graphene on Silicon Photonics

Despite enormous advances in integrated photonics over the last decade, an efficient integrated phase delay remains to be demonstrated. This problem is fundamental – most monolithic thin film deposition relies on centro symmetric materials (such as silicon, silicon dioxide, silicon nitride), which by definition do not have an electro-optic effect. Such materials have been shown to be excellent transparent materials, however they are either optically passive, or rely on very small plasma dispersion effect or power-hungry thermo-optic effect for tunability. These phase change materials have losses associated due to heating or carrier injection in the waveguides. This research shows that graphene can be used to provide electro-optic properties to traditionally passive optical materials.

Posted in: Briefs, Aerospace, Electronic Components, Electronics, Electronics & Computers, Materials, Optical Components, Optics, Photonics

Ultracompact, High-Speed Field-Effect Optical Modulators

The major goals of this research project included two parts. First, an ultracompact plasmonic electro-optical (EO) modulator was to be developed and investigated for efficient intensity modulation. Second, an ultracompact and high-speed EO modulator based on a dielectric platform was to be developed for straightforward integration with existing CMOS technology. Both modulators were targeted to facilitate next-generation interconnects for integrated photonic circuits.

Posted in: Briefs, Aeronautics, Aerospace, Aviation, Joining & Assembly, Mechanical Components, Optical Components, Optics, Photonics, Semiconductors & ICs