Abstract: An iono-refractive structure that includes one or more ion insertion layers having a real portion and an imaginary portion of the dielectric constant is provided. While both the real portion and the imaginary portion of the dielectric constant change, the change in the imaginary portion is less than the change in the real portion at the wavelength of interest or at the operational wavelength. The iono-refractive structure may be suitable for the fabrication of or integration with tunable optical filters, wavelength-selective optical elements, active modulated interferometers, optical phase shifters, optical phased array beam steering, optical phased array beam tracking, tunable optical filters, sensors, variable lenses, tunable diffraction gratings, and other optical components.

Abstract: An iono-refractive structure that includes one or more ion insertion layers having a real portion and an imaginary portion of the dielectric constant is provided. While both the real portion and the imaginary portion of the dielectric constant change, the change in the imaginary portion is less than the change in the real portion at the wavelength of interest or at the operational wavelength. The iono-refractive structure may be suitable for the fabrication of or integration with tunable optical filters, wavelength-selective optical elements, active modulated interferometers, optical phase shifters, optical phased array beam steering, optical phased array beam tracking, tunable optical filters, sensors, variable lenses, tunable diffraction gratings, and other optical components.

Abstract: An iono-refractive structure that includes one or more ion insertion layers having a real portion and an imaginary portion of the dielectric constant is provided. While both the real portion and the imaginary portion of the dielectric constant change, the change in the imaginary portion is less than the change in the real portion at the wavelength of interest or at the operational wavelength. The iono-refractive structure may be suitable for the fabrication of or integration with tunable optical filters, wavelength-selective optical elements, active modulated interferometers, optical phase shifters, optical phased array beam steering, optical phased array beam tracking, tunable optical filters, sensors, variable lenses, tunable diffraction gratings, and other optical components.

Abstract: A highly-sensitive, rapid response fluorescent probe is based on the affinity of a polymer matrix for an analyte of interest. The probe includes a polymer matrix and a dye immobilized in the matrix. The polymer matrix has an affinity for an analyte of interest and the dye has little or no sensitivity to the analyte of interest when excited by an excitation source in a free state but has significant sensitivity to the analyte of interest when excited by the excitation source when immobilized in the matrix. Sensors incorporating the polymer/fluorophore probes of the present invention have the sensitivity and rapid response needed for detection of chemical agent and biological materials. Sensors using the probes provide sensitivity to Sarin at several hundred parts per trillion in one second or less. That is a notable advance over state-of-the-art detectors that require preconcentration steps, which in turn restrict response times to one minute or more.

Abstract: The present invention is a fluorescent probe for detecting chemicals, particularly chemical warfare agents. The probe has a novel selection of polymers and fluorophores that allow for laser excitation and photodiode detection of chemical warfare agents. A probe based on poly(epichlorohydrin) as the polymer and nile blue A perchlorate as the fluorophore is sensitive to concentrations of mustard of less than 30 ppb. Probes based on fluoropolyol as the polymer and oxazine 170 perchlorate as the fluorophore is sensitive to low concentrations of soman. Selecting a cationic fluorophore that has an affinity for the chemical agent of interest and immobilizing that fluorophore in a polymer matrix provides a fluorescent probe capable of detecting the presence of the desired chemical agent in trace quantities. A set of probes may be used so that in the presence of an analyte or a mix of analytes one or more of the probes may be responsive.

Abstract: An instrument for total internal reflection fluorescence spectroscopy having modular probe that inexpensively monitors vapors and liquid-phase analytes under field conditions is described. The system is particularly helpful in evaluating multiple analytes using the fluorescence of a material immobilized in a thin sorbent polymer coating. At the same time, the system is capable of monitoring trace quantities of analyte using a fluorescence-read immunological reaction. The device includes a diode laser source, a shaped optical element (which may be as simple as a microscope slide), and one or more amplified photodiode detectors. The shaped optical element propagates light from the diode laser in a series of internally reflective bounces.

Abstract: The present sensor allows the user of any diode laser structure to be employed to provide sensitive chemical and biological detector. A diode laser electrochemical sensor is described in U.S. Pat. No. 5,591,407 “Laser Diode Sensor”. The present invention surpasses the capabilities of those sensors by measuring changes in the output power, output spectral characteristics or output signal auto-correlation function to detect the presence of chemical or biological films within the sensitive region.

Abstract: An optical fiber fluorescence sensor system capable of compensating fiber bending loss is provided. The system uses a modulated light-emitting diode and digital-signal processing chips to enhance the measurement of fluorescence signals. A fiber-optic oxygen sensor system suitable for measuring oxygen levels in gas and in aqueous media is provided. The system alleviates fiber bending loss. Detection of the signal-to-noise ratio of the system which exceeds 30 dB is done by using inexpensive components.

Abstract: Optical chemical probes have layers of anionic and cationic polyelectrolytes and one or more dyes incorporated into these layers. The probes are placed into the medium and the dye or dyes react in the presence of the corresponding chemical. Color changes may be observed manually or by a photo detector. A light source may be employed to increase the optical signal received from the probe. Further, a waveguide may be used to trap multiple optical signals. The invention is used for chemical analysis.

Abstract: The vibration and electrical characterization of a piezoelectric tactor actuator is described. The actuator is a rectangular laminated flat plate with two opposite sides simply supported and two others free. Under an axial compression from the supports, the plate deforms into a stressed shallow shell. Electrical high frequency harmonic signals within relatively low-frequency bursts are applied to the piezoelectric layers. Depending on the axial compression and pre-deflection, frequency and magnitude of electrical input, the tunable actuator exhibits frequency/mode-controlled high-force over large area vibrations with intense displacement jumps. A single-degree-of-freedom model and simplified 1-D models are provided. The tactor provides efficient conversion of electrical energy into mechanical.

Abstract: A-compact, diode laser-based sensor has applications in biological and chemical analysis. Unlike existing optical waveguide-based sensors, no external coupling to external optical fibers or waveguides is required to perform optical chemical, immunological or nucleic acid-based assay or to detect the presence of toxic or otherwise important chemicals. The sensor includes a surface-sensitive diode laser having a substrate layer, an n-contact layer positioned on a bottom surface of the substrate, an n-clad layer overlying the top surface of the substrate, a first guide layer overlying the n-clad layer, a quantum well layer overlying the first guide layer, a second guide layer overlying the first quantum well layer, a p-clad layer overlying the second guided layer and a p-doped cap layer overlying the p-clad layer. A pair of electrodes separated by a surface-sensitive region is positioned on the cap layer.

Abstract: An apparatus and its accompanying method measures fluorescence decay, fluorescence amplitude and fluorescence polarization. The instrument includes a light emitting diode or laser diode light source, an amplified photodiode detector, and electronics and software for calculating the phase of the fluorescence from the computed inner product of the scattering and fluorescence signals. The electronics for measuring fluorescence decay includes two signal synthesizers, two downconverters, a simultaneously sampling analog-to-digital converter and means for calculating the inner product of the downconverted waveforms. A signal source, preferably a direct digital synthesizer, is used in combination with a digital-to-analog converter to provide a controllable output signal. That signal drives a modulatable light source, which is a light emitting diode, a laser diode or a combination of the two. Excitation light from the light source excites the sample fluorophore which is immobilized in a solid material.

Abstract: Fluorescence measuring methods and apparatus use planar optical waveguides to excite fluorescence in the evanescent field of the waveguides and photodetectors to sense the fluorescence produced. Chemically sensitive fluorophores are bound to the evanescent regions of the planar optical waveguides. Substrates support the waveguides. Photodetectors, positioned in the substrates with fields of view normal to the waveguides, detect the fluorescence. Wavelength-selective material coating surfaces of the photodetectors allow fluorescence to be detected while restricting entry of light at the excitation wavelengths. The photodetectors have high aspect ratios for detection of fluorescence generated by the optical waveguides. Preferably, the photodetectors are closely coupled to the fluorescence generated in the evanescent field of the waveguide.

Abstract: A highly sensitive surface plasmon waveguide sensor monitors the refractive index and thickness of thin adsorbed films. The sensor includes an optical waveguide formed by ion-exchange in a glass substrate, by selective densification of substrate material or by the incorporation of high refractive index materials during deposition of a dielectric layer. Two dielectric thin films are deposited on top of the waveguide. The layer closest to the waveguide has a lower refractive index than the guiding layer to form a buffer layer. The second dielectric layer, or tuning layer, has a higher refractive index. The tuning and buffer layers allow optimization of the resonance wavelength, full-width half maximum of the resonance wavelength range and amplitude of the resonance. The tuning layer is coated with a thin metallic layer, to effect surface plasmon resonance, such as gold, silver, aluminum or one or more semiconducting materials.

Abstract: A chemical sensor uses a semiconductor diode laser having a surface active region. A laser structure, including an active layer, a cladding layer, a barrier layer and a grating layer, is constructed on a substrate. A contact layer is deposited on a surface of the laser structure. One or more electrodes are positioned on the contact layer. A segmented electrode has a first contact pad, a second contact pad, and a surface active region between the first and second pads. A surface active region is created between the two electrodes. The tail of the lasing signal interacts with surface features of the diode laser or with chemical materials or probes in contact with the surface of the diode laser or in contact with coatings on the surface of the diode laser. Chemical changes in the ambient environment induce changes in the laser signal. The modified laser signal output is detected by a detector region integral with or separated from the laser structure.

Abstract: The present invention is a new electronic memory-assist device which can be used to remind an individual when it is time to take a prescribed medicine. The invention uses complementary metal-oxide semiconductor technology in conjunction with surface-mounted device technology to provide a programmable portable unit. The device has three parts: a body-carried reminder, a local interactive compliance processor and a supervisory unit. The reminder has a portable power supply, microprocessors, software, memory, an alarm, an input key and communication linkage to the compliance processor. The compliance processor has a central processing unit, a pill case, a modem and, possibly, a recharger for the portable power supply. The supervisory unit is connected to the central processing unit remotely by modems. The device operates by providing data to the user through an alarm that it is time to take prescribed medication. The alarm is visual, auditory, tactile or any combination of the three.

Abstract: A fluorescent sensor for chemical analysis has a light source, an optical waveguide, and a detector. Fluorophores are associated with the optical waveguide. When an impervious waveguide is used, a fluorophore-containing layer is applied to a surface of the waveguide. The fluorophores are excited by a laser, a light emitting diode, an electroluminescent source or a lamp source emitting light propagating at angles to the waveguide. The light source is modulated. A mirror can be used to direct the light beam. The angle of light incidence on the waveguide can be altered by moving the waveguide itself. The waveguide traps the laser-induced fluorescence and projects fluorescence signals through a suitable filter to a photodetector or otherwise wavelength-specific photodetector positioned near the waveguide structure. Remote operation of the sensor is achieved using optical fibers. Patterned waveguides allow multiple excitation sources to illuminate multiple fluorescent probe materials.

Abstract: An instrument is applied to the measurement of chemical species and concentration through the use of a chemically-sensitive coating on the eddy current coil or in the vicinity of the eddy current coil which produces a change in impedance of the probe through induced eddy currents in the coating. An eddy current or resonance circuit chemical detector is a non-contact sensor for measuring chemical species identity and concentration. The chemical detector is resilient and does not require reference electrodes. The chemical sensor is selective as a result of data available on the change in vector impedance of the probe, the change in resonant frequency of the tuned circuit, and the availability of data to construct a vector response from multiple probes having differing chemistries. The probe is used in extreme temperatures.

Abstract: Alumino-silicate glass-ceramic coated carbon-carbon composite and graphitic substrates having resistance to oxidation and thermal cycling. The coatings are fabricated from plasma-sprayed powders of beta-spodumene, cordierite, beta-eucryptite or beta-quartz and are rapidly recrystallized by laser processing.

Abstract: Wood composite materials containing veneer layers interposed with a thermoplastic adhesive containing a polyester such as polyethylene terephthalate and other thermoplastic polymer show increased impact resistance. The composite material may be manufactured using an adhesive transfer method or film extrusion.