Abstract: Methods and systems for extracting energy from a heat source using photonic crystals with defect cavities generally comprise a photonic crystal, a cavity, and a converter. The photonic crystal is responsive to a heat source and generates an electromagnetic beam in response to incidence with the heat source. The photonic crystal exhibits a band gap such that wavelengths within the band gap are substantially confined within the photonic crystal. The cavity is substantially within the crystal and is responsive to the electromagnetic beam such that the cavity transmits the electromagnetic beam to a specified location. The converter is substantially collocated with the specified location and extracts energy in response to incidence with the electromagnetic beam.

Abstract: A quantum computing device and method employs qubit arrays of entangled states using negative refractive index lenses. A qubit includes a pair of neutral atoms separated by or disposed on opposite sides of a negative refractive index lens. The neutral atoms and negative refractive index lens are selectively energized and/or activated to cause entanglement of states of the atoms. The quantum computing device enjoys a novel architecture that is workable and scalable in terms of size and wavelength.

Abstract: An imaging system (20) includes an array (24) of photonic band gap material cells. The band gap material has an absorption edge at about the emission frequency of a source (22) of electromagnetic energy. Images from a field of view (26) directed onto the photonic band gap array (24) increase the temperature of the illuminated cells, shifting the absorption edge frequency for those cells. A focal plane array (28) detects the electromagnetic radiation transmitted through the photonic band gap array (24) from the source (22). The intensity of the transmitted radiation is proportional to the shift in the photonic band gap edge.

Abstract: The Smith Purcell effect, in which a beam of electrons passes close to a conducting grating and induces electromagnetic radiation from the grating surface, can be used as a source of THz radiation. A grating composed of negative index metamaterial (NIM) enhances the output of the Smith Purcell source. Of particular interest is the use of a NIM grating in a Smith-Purcell source to provide a tunable coherent CW source of terahertz (THz) radiation.

Abstract: A system and method for modulating the frequency of electromagnetic radiation utilizes a frozen shockwave in a photonic band gap structure. The structure provides a discontinuity in lattice constant that functions as a shockwave, and that does not shift its position within the structure. In addition the modulation device or structure includes an acoustic pulse generator, such as a piezoelectric transducer coupled to one end of the photonic band gap structure. The acoustic pulse generator may be driven to produce a periodic pulse in the photonic band gap structure. The frozen shockwave, a defect or discontinuity in the photonic band gap structure, is used to hold incoming electromagnetic radiation in place. The acoustic pulse passing through the photonic band gap structure Doppler shifts the frequency of the radiation. The frequency-shifted radiation is then ejected out of the frozen shockwave portion of the photonic band gap structure.

Abstract: An apparatus (10) and method for dynamic frequency control of a photonic band gap crystal includes an acoustic band gap crystal (12) having a defect site (14), a photonic band gap crystal (20) in the defect site of the acoustic band gap crystal (12), and a sound wave generator (40) coupled to the acoustic band gap crystal (12). Consequently, acoustic waves in the acoustic band gap crystal (12) can be used to controllably alter transmission properties of the photonic band gap crystal (20) and thereby modulate the transmission of electromagnetic radiation through the photonic band gap crystal (20). Acoustic waves in the acoustic band gap crystal (12) can squeeze the photonic band gap crystal (20) to change its properties, including one or more of lattice constant, symmetry, and optical refractive index contrast.

Abstract: A band gap discontinuity is propagated across a Photonic Crystal (PC) to capture thermal energy in a region near the primary emission wavelength of the Planck spectral distribution and transfer that energy to a different spectral region where it is emitted. To extend the range of frequency shifting beyond the width of a single band gap, the intrinsic control parameters (e.g., lattice geometry factors, scattering element geometric factors, and variations in the index of refraction) are spatially varied across the PC to form a band gap gradient. Propagation of the band gap discontinuity, starting in the infrared wavelength region where the thermally generated electromagnetic energy is concentrated and propagating towards the long wavelength region, locally captures the thermal electromagnetic radiation, shifts it downwards in frequency, and pushes the lower-frequency thermal electromagnetic radiation on to the next region. The same principles apply to shift the frequency to shorter wavelengths.

Abstract: On-chip multispectral imaging and data management is provided in the form of an Adaptive Focal Plane Array (AFPA) that is capable of spectral tunability at the pixel level. Layers of photonic crystals are registered with pixels of a broadband focal plane array. Spectral tuning is accomplished by switching the photonic crystal layers on/off and/or by changing their material structure to tune their photonic band gaps and provide a passband for incident photons. The photonic crystal layers are preferably segmented to independently address different regions or “cells” of pixels down to a pixel-by-pixel resolution. The AFPA may simultaneously sense different regions of a scene at different spectral wavelengths, spatial resolutions and sensitivities.

Abstract: Although THz radiation is naturally emitted by hot objects, the intensity levels are too weak to be considered as a practical THz source for most applications. Photonic crystal structures are used to modify the thermal emission peak associated with the standard Planck blackbody spectral distribution so that the THz region is dramatically enhanced. The photonic crystal core is preferably combined with variable Q defect cavities and a wave guiding and power combining structure so that the radiated THz energy is efficiently collected and directed to an output antenna. Higher THz emissions are realized by embedding a finer (higher frequency) photonic crystal structure within a coarser (lower frequency) structure.

Abstract: An identification system for identifying objects of interest is disclosed. The system includes an enhancement mechanism for enhancing Raman scattering from a plurality of Raman active molecules (RAMs). An interrogator transmits a signal toward an object of interest and receives a return signal therefrom. The return signal includes a Raman signature, and the interrogator classifies the object based on the Raman signature.

Abstract: A device is provided that can capture and store electrically neutral excited species of antimatter or exotic matter (a mixture of antimatter and ordinary matter), in particular, excited positronium (Ps*). The antimatter trap comprises a three-dimensional or two-dimensional photonic bandgap (PBG) structure containing at least one cavity therein. The species are stored in the cavity or in an array of cavities. The PBG structure blocks premature annihilation of the excited species by preventing decays to the ground state and by blocking the pickoff process. A Bose-Einstein Condensate form of Ps* can be used to increase the storage density. The long lifetime and high storage density achievable in this device offer utility in several fields, including medicine, materials testing, rocket motors, high power/high energy density storage, gamma-ray lasers, and as an ignition device for initiating nuclear fusion reactions in power plant reactors or hybrid rocket propulsion systems.

Abstract: A compensated radome is provided, comprising an inner layer of a negative index of refraction material, often referred to as a “metamaterial”, and an outer layer of a positive index of refraction material. The thickness of the two materials and their respective refractive indices are adjusted so that a beam of light passing through the radome is effectively not refracted. The metamaterial-compensated radomes solve the bore sight angle problem with a minimum of complexity.

Abstract: A compensated radome is provided, comprising an inner layer of a negative index of refraction material, often referred to as a “metamaterial”, and an outer layer of a positive index of refraction material. The thickness of the two materials and their respective refractive indices are adjusted so that a beam of light passing through the radome is effectively not refracted. The metamaterial-compensated radomes solve the bore sight angle problem with a minimum of complexity.

Abstract: A method of absorbing microwave radiation is provided. The method comprises placing a structure in the path of the microwave radiation, the structure comprising an array of metal plates supported over a metal substrate by vertical conducting vias. The structure finds specific use in missiles having a dome portion that operates in a stealth mode. At least the inside of the dome portion is provided with the above-described structure for absorbing microwave radiation. The structure also finds use in anechoic chambers for use in testing microwave-emitting devices. Such anechoic chambers have walls, a floor, and a ceiling, which are provided with the above-described structure for absorbing microwave radiation. Surface patterning is thus used to enhance the micro-wave absorption. In addition, the frequency over which the material is highly absorptive can be shifted by changing the height of the structure, thus allowing active control (“tunable in real time”).

Abstract: An optical/electromagnetic fiber capable of high power transmission comprises an air core surrounded by a left-handed meta-material (LHM). Conventional optical fibers need more power capacity. While photonic band gap-based optical fibers may be sufficient, left-handed materials provide new options for designers.

Abstract: A method for measuring acceleration uses an accelerometer apparatus having an optically transparent, stress-birefringent material, a source of polarized light positioned to direct a polarized beam of light into the optically transparent, stress-birefringent material, and a detector system positioned to detect an output beam from the optically transparent, stress-birefringent material. The accelerometer apparatus is accelerated, and the acceleration of the accelerometer apparatus is simultaneously determined from a measurement of stress-induced optical birefringence in the optically transparent, stress-birefringent material.

Abstract: A radar antenna for a guided missile is calibrated in flight using a point source of microwave radiation and a lens to emulate a far field source. The microwave source and lens fit behind a metal cap at the leading end of the radome and so do not adversely affect the radar. A variety of techniques to power the point source are disclosed, and a variety of lens arrangements are disclosed. The invention allows a radar antenna to be calibrated in flight, and so insures against mis-calibration due to aging components as well as the heat and mechanical forces associated with storage and/or launch of the missile.