Physical Sensors Optics

Imaging apparatus and method 6,594,011

Imaging apparatus and method which uses change of polarization state of a light beam passed through a total internal reflection structure by a single reflection at a TIR surface in which a specimen is placed in the evanescent field associated with the total internal reflection of the light beam, the specimen being the subject of biological, chemical or genetic investigation.

Optical signal active tracking using tunable FBG 6,696,682

A method and apparatus for processing an optical signal in an optical waveguide using a closed loop wavelength dependent active tuning system. A tunable fiber Bragg grating, optical processor and a controller provide feedback control of the central wavelength of the tunable fiber Bragg grating. Changes in wavelength of the processed signal are followed to keep the tunable fiber Bragg grating tuned to a peak wavelength for maximum sensitivity.

Birefringent fiber grating sensor and detection system 6,201,912, 6,208,776

A sensor system comprises a broadband light source, a birefringent sensor, a detection circuit, and a signal processing unit. The preferred detection circuit further includes a variable frequency oscillator, a modulator, and a photodetector. The modulator modulates the output of the birefringent sensor with a modulation signal from the variable frequency oscillator. The modulation produces an interference signal having a variable interference frequency. By determining the frequency of the modulation signal from the variable frequency oscillator that minimizes the interference frequency, the detection system is able to determine the difference in frequency between first and second spectral components of the output of birefringent sensor.

Tunable filter 6,650,810

A tunable optical filter for simulating the waveband spectrums of selected substances. The filter includes an optical waveguide with a core material for transmitting light energy and a nominal core refractive index for the core material. Predetermined periodic variations are formed in the core material of the optical waveguide between the input and output ends that alter the core refractive index of the waveguide at the location of the periodic variations. Depending upon the periodic variations, the waveguide produces a predetermined reference waveband spectrum output that matches the waveband spectrum of a selected substance.

Interfacial propagating mode waveguide 6,282,338

An optical fiber waveguide including a selected period reflection grating structure for coupling the forward propagating mode of an optical signal transmitted through the waveguide into a backward propagating interfacial mode where a substantial portion of the optical signal is propagated in the cladding region of the fiber.

Surface plasmon resonance apparatus and method 6,667,807

A surface plasmon resonance device includes a metal thin film, a dielectric thin film on an optical member and, in addition, an electro-optically active thin film either between the metal thin film and the dielectric thin film or between the optical member and the metal thin film. The electro-optically active thin film is subject to a voltage which is varied to tune the resonance condition of the device.

Optical waveguide illuminator 6,714,711

Methods and apparatus for producing an optical waveguide illuminator are disclosed. By controlling the propagation of light in the core and cladding regions of the waveguide, distributed light emission along a length of an optical fiber or along a planar waveguide surface can be achieved by varying the core/cladding refractive index ratio and introducing light scattering centers in the core.

Method and system for determining the wavelength of light transmitted through an optical fiber 6,052,179

A method of determining the wavelength of light transmitted in an optical fiber comprises the steps of filtering the light using a filter, and then detecting the filtered light, and then determining the wavelength of the filtered light.

Self-referencing interferometric fiber optic sensor system having a transducer mechanism with a position reference reflector 6,014,215

A fiber optic sensor system comprises an optical fiber, a first reflector and a second reflector. The first reflector provides a fixed reference for measuring the optical path length between the second reflector and a reference reflector. The first and second reflectors respectively receive first and second portions of light emitted by the optical fiber and then reflect the light back to the optical fiber. The optical path length between the first and second reflectors varies in accordance with a sensed parameter.

Modular fiber optic fluorometer and method of use thereof 5,994,707

A low cost portable fiber optic fluorometer is packaged as a personal computer peripheral and is based on interchangeable modules. One embodiment of the fluorometer comprises an excitation source, a detector, a signal processor, frequency source, wavelength selector, and an optical interface. The optical interface is exclusively fiber optic-based, thereby simplifying optical alignment and reducing the cost of the fluorometer. In another embodiment, the excitation source is an inexpensive monochromatic excitation source. In this case, the monochromatic excitation source and the first wavelength selector are preferably removable and replaceable, so that the fluorometer is advantageously able to generate different excitation wavelengths and detect different emission wavelengths.

Surface plasmon resonance sensor and methods for the utilization thereof 5,485,277

A surface plasmon resonance sensor including: a substrate-mode metal film coated waveguide cartridge including: a planar waveguide including a plurality of reflector surfaces within the planar waveguide; and a metal film deposited directly on the planar waveguide, the metal film and the planar waveguide defining a plasmon resonance interface directly on the planar waveguide; a sample flow cell adjacent the substrate-mode metal film coated waveguide cartridge; a transverse magnetic polarized light source optically connected to the planar waveguide; a cylindrical diverging lens optically connected to the planar waveguide; and a detector array comprising a plurality of photodetectors optically connected to the cylindrical diverging lens.

Photonic band-gap light-emitting fibers 6,470,127

A photonic band-gap (PBG) light-emitting fiber, including two-dimensional PBG structures in an environmentally robust glass matrix. The fiber limits photon emission to directions collinear with the fiber core to increase fluorescence and scintillation collection efficiency. The PBG structures are comprised of a plurality of high refractive index inclusions to increase the light-trapping efficiency of the fiber.

Surveillance system and method 6,954,142

A sensor system in which a sensor suite has a locally located field sensing unit (FSU) that converts and evaluates sensor information using sensor fusion algorithms and is thereby able to send qualitative low-bandwidth, low power usage signals to a remote command post.

Enhanced non-steady-state photo-induced electromotive force detector 6,342,721

A photo-EMF detector for the collection of photons includes a substrate formed of a photorefractive semiconductor and a plurality of interlaced electrode pairs disposed over the substrate. Each electrode pair includes two parallel electrodes defining an active area therebetween for the collection of photons. One electrode of each pair is disposed between an adjacent pair of electrodes and proximate one electrode of the adjacent pair, light from striking a substrate surface between proximate electrodes and outputs from each of the plurality of interlaced electrode pairs are collected.

Enhanced photo-EMF sensor with high bandwidth and large field of view 6,818,880

A photo-EMF sensor and a method of making same has a substrate with a semiconducting layer; a plurality of sensing regions in the layer, each sensing region including (i) a pair of electrodes disposed in, on or above the layer and (ii) an active region in the layer disposed adjacent said pair of electrodes; and a plurality of inactive regions in said the arranged between adjacent sensing regions.

Incapacitating flashing light apparatus and method 7,180,426

Apparatus and method for using an light source to incapacitate a subject in which the light source strobes by a spatial scanning through a pattern and a temporal flashing at a rate sufficient to cause incapacitation. The strobing (meaning both spatial scanning and temporal flashing is in a pattern to prevent the subject from escaping the strobing effect. The flashing is timed so that each flash point in the pattern will flash at a rate and sequence to cause incapacitation. In a preferred embodiment, the light source is an array of LEDs or laser diodes.