John T. Apostolos

Low-power stimulated emission nuclear quadrupole resonance detection system utilizing Rabi transitions

The application of CW radar techniques to Nuclear Quadrupole Resonance (NQR) detection of nitrogen based explosives and chlorine based narcotics enables the use of low power levels, in the range of 10’s of watts, to yield high signal strengths. By utilizing Rabi transitions the nucleus oscillates between states one and two under the time dependent incident electromagnetic field and alternately absorbs energy from the incident field while emitting coherent energy via stimulated emission. Through the application of a cancellation algorithm the incident field is eliminated from the NQR response, allowing the receive signal to be measured while transmitting. The response signal is processed using matched filters of the NQR response which enables the direct detection of explosives. This technology has applicability to the direct detection of explosives and narcotics for security screening, all at safe low power levels, opposed to the current XRay and Millimeter wave screening systems that detect objects that may contain explosives and utilize high power. The quantum mechanics theoretical basis for the approach and an application for a system for security screening are described with empirical results presented to show the effects observed.

Armor embedded antennas for land vehicles

Through the armys Breakthrough Antenna Technology (BAT) Army Technology Objective - Research (ATO-R), S&TCD is pursuing to push the frontiers of antenna technology for the future warfighter. BAE Systems and the U.S. Army are developing antennas that are embedded into the armor of vehicles without impacting the armors performance. Two main challenges drive the complexity of the design: 1. the dielectric properties of the armor material, and 2. the design of a radiating element with minimal impact to the armor structure. Measuring the dielectric properties of the armor material is necessary to employ accurate simulation models during the antenna design effort. Minimizing the impact to the armor structure is part of the larger goal of no degradation in ballistic performance of the armor due to the antenna integration.

Stand-Off Explosive Detection Utilizing Low Power Stimulated Emission Nuclear Quadrupole Resonance Detection and Subwavelength Focusing Wideband Super Lens

The need for advanced techniques to detect improvised explosive devices (IED) at stand-off distances greater than ten (10) meters has driven AMI Research and Development (AMI) to develop a solution to detect and identify the threat utilizing a forward looking Synthetic Aperture Radar (SAR) combined with our CW radar technology Nuclear Quadrupole Resonance (NQR) detection system. The novel features include a near-field sub-wavelength focusing antenna, a wide band 300 KHz to 300 MHz rapidly scanning CW radar facilitated by a high Q antenna/tuner, and an advanced processor utilizing Rabi transitions where the nucleus oscillates between states under the time dependent incident electromagnetic field and alternately absorbs energy from the incident field while emitting coherent energy via stimulated emission. AMI’s Sub-wavelength Focusing Wide Band Super Lens uses a Near-Field SAR, making detection possible at distances greater than ten (10) meters. This super lens is capable of operating on the near-field and focusing electromagnetic waves to resolutions beyond the diffraction limit. When applied to the case of a vehicle approaching an explosive hazard the methodologies of synthetic aperture radar is fused with the array based super resolution and the NQR data processing detecting the explosive hazard.

Wideband Coherent Optical Concentrator for Photovoltaic and Rectenna Solar Cells

A wideband coherent optical 1D concentrator, intended for rectennas, has been designed with an integrated photovoltaic array solar cell. Modeled and measured results are presented for a wedge prism coupled SiON waveguide array.