We consider the possibilities of developing smart nano-structured coverings that allow one dynamically change their color in the reflected light by modify spectral position of their reflection coefficient. The suggested technology is based on the recent progresses in the field of photonics and the fabrication of silicon-compatible photonic band gap (PBG) materials, photonic crystals. It is suggested to compose the PBG structures of porous silicon and infiltrate them with active nano-compounds whose optical features can be changed by the application of the electric field, current or illumination. As a result, the controlled change of color of the composed structure can be achieved.
We develop laser-based technologies for characterization and release of Surface Tension Energy (STE) in nanoparticle structures. Nanoparticle dispersed materials offer a very high potential to store energy in the form of Surface Tension. An important benefit of these systems is the increased safety and control of energy storage compared to existing chemical systems. The release technology is based on excitation of resonant plasmons in metal nanoparticles and their further laser-induced coalescence, whereas the characterization technology is related to the extraordinary sensitivity of nonlinear optical effects in nanoparticles to their surface conditions and properties. The direct relation between STE and nonlinear optical parameters of nanoparticles permits use of optical second-harmonic generation (SHG) to measure STE. The SHG probe can be applied to characterize surface properties of a wide variety of nanoparticle materials, particularly active and smart materials. In terms of surface energy elease, we concentrate on nanoparticle-dispersed materials in the form of arrays of metal nanoparticles. External laser radiation is considered to trigger interparticle coalescence due to excitation of local plasmons that are specific electro-magnetic modes in metal nanoparticles. Local plasmon excitation, in turn, lead to surface energy release in the wake of fusion of excited nanoparticles.
Bad things often happen fast. This means that we need to react fast. In this work, we develop the technology that allows one to identify and characterize fast events. In real time, we dynamically process hyperspectral information of a scene, specifically analyzing its temporal behavior. The goal is to detect fast and super-fast events like explosions, fast-moving objects and instant changes in the chemical composition of air and other materials. Until recently, the enormous quantity of hyperspectral information confined us to static hyperspectral data processing. Hyperspectral techniques were used for finding certain objects, chemicals, or anomalies in a picture, frame by frame, statically. Dynamic (temporal) analysis was developed primarily for astrophysical applications performed a long time after the frames had been captured. In this work, we study ways of taking advantage of emerging hardware technologies that allow one to look at hyperspectral information dynamically: by characterizing temporal changes as they occur. We apply methods from astrophysics (supernova observations) and present our unique algorithms for contemporaneous dynamical analysis of hyperspectral data. The application addresses the question: have there been any sudden changes in the hyperspectral pattern of a scene? If there were sudden changes, were those changes related to a substantial energy release? These questions do not depend on assumptions about specific spectral patterns, chemical composition, or shapes: we look for any changes in a scene. Such dynamical analysis can therefore allow one to react promptly to fast events without prior knowledge about what occurred. This paper addresses issues specific to dynamic (as opposed to static) hyperspectral imaging, algorithmic approaches to dynamic hyperspectral data processing, and associated hardware-implementation issues.
This paper describes a radiation source that can be used to actively interrogate containers, trucks, trains, cars, etc to determine the presence and location of chemical explosives and special nuclear materials such as uranium and plutonium. Active interrogation methods using high energy photon or neutron sources to induce fission are the only feasible option for detection of highly enriched uranium (HEU) because passive detection methods are easily compromised by even moderate amounts of shielding. For detection of chemical explosives, the same active interrogation device can be used to produce resonant photons that can detect nitrogen that is used in most chemical explosives. The accelerator based system described here produces a penetrating beam of high energy photons or neutrons that can "see" inside a sealed container. If chemical explosives or special nuclear materials are present, they will emit a characteristic signal that is detected and interpreted by electronic sensors. Shielded “dirty bombs” can be detected by the attenuation of high energy photons caused by the density of the shield material. The interrogating source of radiation is based upon a new high current negative ion source and high current tandem accelerator. The accelerator accelerates ions and projects them onto an appropriately designed target. The target converts the energy of the ion beam into a high energy highly penetrating photon or neutron beam. The beam is made to pass through the container. If explosives, special nuclear materials or shielded dirty bombs are present, the beam together with a suitable detection system uniquely identifies the location, amount and density of material.
Nano-coatings with adjustable optical features is one of the revolutionary technologies of today. In this work, we investigate how hyperspectral imaging can detect adjustable nano-surfaces used, for example, for active camouflage. The distinct attributes of the nano-coating spectra are discussed. Fast algorithms of utilizing hyperspectral information for recognizing these attributes are suggested. The research applies to both recognizing the camouflaged objects and to building unrecognizable camouflage technology. In the context of tracking active camouflage, the identification of
characteristic spectral attributes is especially important. Active spectra can constantly change, therefore confusing traditional hyperspectral classification. In contrast, the identified general spectral attributes stay the same allowing for robust identification and reliable tracking of the camouflaged objects.
We have developed an innovative method using radiation produced by in flight annihilation of energetic positrons to detect hidden explosives and other illegal substances. The system uses either radioisotope or compact accelerator based methods to generate a high energy positron beam. The high energy positrons annihilate in flight producing a tunable, narrow spectrum beam of high energy photons. The photon energy, which is determined by the positron energy, can be chosen to be resonant with elements of the explosive or other target. The concentration of the target material determines the intensity of the return signal. Standard gamma radiation detection techniques are used to detect the emitted gamma rays. Because of the innovative method we use to generate and monochromatize the positron beam, the entire system is inexpensive, compact and portable.