USA As Represented by Secretary of the Navy

Other

Temple University

Dong Ho Wu

Benjamin S Graber

Anthony Garzarella

Rongjia Tao

Christopher Kim

Louis M Pecora

Systems and methods are provided for enhancing the terahertz power output of a terahertz beam while increasing its stability and its beam polarity by implementing a pair of pinched ripple electrodes and a small flat section in the middle of each electrode. By using tight control over the design parameters and by exploiting the plasmonic effect and the superradiance effect, systems and methods according to embodiments of the present disclosure can achieve a dramatic improvement in the terahertz output power and beam quality as well as the beam stability.

High power broadband terahertz emitter with enhanced stability and beam polarity

Methods and systems for detecting nuclear material concealed within an enclosure are provided. An ionized air density is measured at one or more locations outside of the enclosure. The presence of the concealed nuclear material is detected, for each of the one or more locations, based on a characteristic of the measured ionized air density indicative of concealed nuclear materials.

Systems and methods for detecting concealed nuclear material

An ultra-sensitivity optical-fiber magneto-optic field sensor includes an input fiber passing optical power from an optical source into the sensor; a polarizer optically coupled to and downstream of the input fiber; an analyzer optically coupled to and downstream of the polarizer; an output fiber passing optical power out of the sensor to a photoreceiver; and a magneto-optic crystal element optically coupled between the polarizer and the analyzer. The ultra-sensitivity optical-fiber magneto-optic field sensor has an optical axis extending between the input and output fibers along which a beam of optical power is transmitted.

Apparatus and system for an ultra sensitivity magneto-optic sensor for high sensitivity magnetic field detection and measurements

Systems and method are provided for producing portable, high power, broadband terahertz emitters based on arrayed terahertz photoconductive antennas. After such an arrayed structure is made, the phase of terahertz signals that are produced by each photoconductive antenna can be adjusted, and the terahertz signals can be added such that the signals are added constructively. Terahertz emitters based on terahertz photoconductive antenna arrays are advantageously small in size and scalable, allowing for terahertz power to be increased by adding more photoconductive antenna arrays.

High power terahertz photoconductive antenna array

Systems and methods for remotely detecting nuclear and non-nuclear materials such as chemical agents and gas-phase explosives are disclosed. Nuclear and non-nuclear materials may be detected by transmitting electromagnetic energy toward a remote target area, collecting scattered electromagnetic energy reflected from the remote target area, analyzing an absorption spectrum of the collected scattered electromagnetic energy, and detecting a presence of at least one nuclear or non-nuclear material in the remote target area based on the analyzed absorption spectrum.

Methods and systems for remotely detecting hazardous materials using electromagnetic energy

A system and method for detecting and identifying nuclear materials by detecting and measuring positive and negative ions in multiple ion chambers, wherein each ion chamber comprises a different gas, including oxygen, argon, nitrogen, carbon dioxide, and humid air, and one or more ion counters. The ion data can be transmitted to an isotope identification module. The ion data can include a distinctive pattern data of positive-ion production rates and negative-ion production rates generated from the measured positive and negative ions. The isotope identification module can compare the pattern data of positive-ion production rates and negative-ion production rates to an isotope data library, and identify a detected nuclear isotope with the isotope identification module. A display can show the identified detected nuclear isotope; a probability of the presence of the detected nuclear isotope; and a radioactivity of the detected nuclear isotope.

Remote detection and identification of nuclear materials using multiple ion-chambers

A photoconductive antenna is described that includes a substrate that includes a pair of trenches. Furthermore, a pair of non-parallel electrodes, which can be designed with a chaotic electrode geometry, can each be deposited in one of the trenches, and can be configured to produce chaotic trajectories of incoherent electric currents. Finally, an insulation layer, which can be either a physical electrical insulation layer or an air gap, can be included between each of the pair of non-parallel electrodes and the trench walls. Overall, the thickness of the substrate, the thickness of the trenches, and the thickness of the non-parallel electrodes can each be optimized to produce a coherent terahertz beam.

High power, broadband terahertz, photoconductive antennas with chaotic shape electrodes

An apparatus, for measuring an applied electrical field and for reducing perturbation to the electrical field being measured, includes a laser integrated into an electro optic crystal sensor head prior to the output fiber. A probe beam is passed along the crystal direction of low birefringence of nearly circular optical indicatrix, rather than one of high EO modulation. The EO crystal is placed between two crossed polarizers and oriented such that a small tilt angle is subtended between its optic axis and the path of the probe beam. Improved optical coupling is achieved by using a large core multimode fiber at the output, to reduce optical insertion losses. A collimating lens emits the intensity modulated laser beam back to a photodetector, where the intensity modulated laser beam is converted to an electrical signal representing both field strength and phase of the electrical field applied to the sensor head.

Apparatus and system for a quasi longitudinal mode electro optic sensor for high power microwave testing

A method and a system are implemented in the fabrication of a portable high power terahertz beam source that can produce a tunable, high power terahertz beam over the frequency from 0.1 THz to 2.5 THz. The terahertz source employs a recycling pump beam method and a beam quality control device. The beam quality control device may or may not be required for a high power terahertz beam generation. In exemplary embodiments, a lithium niobate (LiNbO) crystal or a lithium niobate crystal doped with 5% magnesium oxide (LiNbO:MgO) can be used. Other nonlinear optical crystals, including GaSe can be used in place of the LiNbOcrystal. Through proper alignment of a pump beam, along with recycling a pump beam, high conversion efficiency is achieved, and a high output power beam is produced at terahertz frequencies.

Recycling pump-beam method and system for a high-power terahertz parametric source

An apparatus, for measuring an electric field while minimally perturbing the electric field being measured, includes an analyzing stage and a sensor head. The sensor head is optically coupled to the analyzing stage by a laser probe beam transmitted from the analyzing stage. The sensor head includes an electro optic crystal disposed between two gradient index lenses, where the first gradient index lens emits a laser beam transmitted from the analyzing stage to the sensor head, where the electric field is applied and where, the electro optic crystal transforms the laser beam probe into a phase modulated laser beam. The second gradient index lens transmits the phase modulated laser beam back to the analyzing stage, where polarization optics and a photodetector convert the phase modulated laser beam into an electrical signal representing field strength and phase of the electric field.

Growing community of inventors

Olney, MD, United States of America

Dong Ho Wu