Abstract:
A light fixture, using one or more solid state light emitting elements utilizes a diffusely reflect chamber to provide a virtual source of uniform output light, at an aperture or at a downstream optical processing element of the system. Systems disclosed herein also include a detector, which detects electromagnetic energy from the area intended to be illuminated by the system, of a wavelength absent from a spectrum of the combined light system output. A system controller is responsive to the signal from the detector. The controller typically may control one or more aspects of operation of the solid state light emitter(s), such as system ON-OFF state or system output intensity or color. Examples are also discussed that use the detection signal for other purposes, e.g. to capture data that may be carried on electromagnetic energy of the wavelength sensed by the detector.
Abstract:
An apparatus for enhancing the selectivity for spectroscopic measurements of analytes in a turbid medium is described. In one example, spatial filters are used to select only certain radii from the medium to be imaged. This selection is accomplished by placing an optical obstruction on the surface of the medium or at an image plane of the surface later in the optical imaging system. In one implementation, this is achieved by placing a fiber bundle at an image plane of the collecting optical system and then using a spacer of appropriate size at the center of the fiber bundle to act as a central obstruction.
Abstract:
A method is provided for biosensing using a photonic crystal fiber having a hollow core. The method includes: designating an analyte of interest; determining a wavelength for an excitation light source which generates a Raman spectrum when incident upon the analyte of interest; selecting a photonic crystal fiber that would guide the light when the fiber is non-selectively filled with a solvent hosting the analyte of interest; non-selectively filling a photonic crystal fiber with the solvent hosting the analyte of interest; interrogating the analyte of interest by coupling light from the light source to the photonic crystal fiber; and analyzing the light output from the photonic crystal fiber for Raman fingerprints.
Abstract:
A device for determining the surface topology and associated color of a structure, such as a teeth segment, includes a scanner for providing depth data for points along a two-dimensional array substantially orthogonal to the depth direction, and an image acquisition means for providing color data for each of the points of the array, while the spatial disposition of the device with respect to the structure is maintained substantially unchanged. A processor combines the color data and depth data for each point in the array, thereby providing a three-dimensional color virtual model of the surface of the structure. A corresponding method for determining the surface topology and associated color of a structure is also provided.
Abstract:
Performing high-resolution determination of the relative shift of the spectral properties of a biosensor. The shift in the resonance peak of the biosensor is indicative of the amount of material bound to the surface of the biosensor. A preferred biosensor is a Guided Mode Resonant Filter Biosensor (GMRFB). In one aspect of the invention, curve fitting is used to determine the relative location of the spectrum of the unexposed biosensor with respect to those spectra that are altered (e.g., shifted) by the presence of materials bound to the surface of the biosensor. In an alternative embodiment, the cross correlation function is used to detect spectral peak offsets between a reference spectrum and a spectrum measured from an exposed biosensor. In yet another alternative, maximal likelihood estimation techniques are used to determine the spectral shift or offs.
Abstract:
A method for detecting an ingredient in a food product or detecting a disease includes allowing a food sample solution obtained from a food product or a body fluid from an individual to come to contact with a nano-scale surface structure in a sensor, wherein the nano-scale surface structure comprises a plurality of columns over a substrate or a plurality of holes in a substrate. The method includes illuminating the food sample solution or the body fluid on the nano-scale surface structure on the sensor by a laser beam; obtaining a Raman spectrum from the scattered light using a spectral analyzer; and identifying the spectral signature in the Raman spectrum to determine the existence of the chemical substance in the food product or identifying a disease in the individual.
Abstract:
An apparatus and method for noninvasive determination of analyte properties of human tissue by quantitative infrared spectroscopy to clinically relevant levels of precision and accuracy. The system includes subsystems optimized to contend with the complexities of the tissue spectrum, high signal-to-noise ratio and photometric accuracy requirements, tissue sampling errors, calibration maintenance problems, and calibration transfer problems. The subsystems can include an illumination/modulation subsystem, a tissue sampling subsystem, a data acquisition subsystem, a computing subsystem, and a calibration subsystem. The invention can provide analyte property determination and identity determination or verification from the same spectroscopic information, making unauthorized use or misleading results less likely than in systems that use separate analyte and identity determinations. The invention can be used to control and monitor individuals accessing controlled environments.
Abstract:
The invention discloses a multi-wavelength semiconductor light source comprising a plurality of semiconductor light sources mounted on a silicon sub-carrier and emitting radiation spanning a wavelength range. In preferred embodiments, these sources are configured in a linear and circular array. The radiation is coupled to a waveguide array disposed on the same silicon subcarrier, with a lower cladding of silicon dioxide and deposited core layer which is preferably the spin-on epoxy resin SU-8. Output from the waveguide array provides a compact multi-wavelength laser source with wide tuning range via a plurality of laser sources. An output spatial span of the waveguide array is smaller than an input spatial span and sufficiently small to probe the properties of a sample. A compact system for optical spectroscopy is constructed from the multi-wavelength semiconductor light source, a means for directing radiation from the source to a sample, and an optical detector configured to detect one of a radiation reflected from and transmitted through said sample. In various preferred embodiments, the semiconductor light sources can comprise lasers, light-emitting diodes, and superluminescent diodes.The system for optical spectroscopy can be used in a variety of applications including the analysis of in-vivo human tissue, agricultural samples, and pharmaceutical samples. Typical wavelength ranges for these and other applications include 650-1000 nm, 700-1700 nm, and 1100-2500 nm.
Abstract:
An optical spectrum analyzer and a method of spectrally analyzing an optical signal. The optical spectrum analyzer includes a wave shaper such as an optical modulator that shapes an optical signal, a dispersive element such as a dispersive fiber in which the shaped optical signal is dispersed, a detector that provides an output signal indicative of the dispersed shaped optical signal, and a signal processor that analyzes the output signal, for example by calculating a transform such as an inverse Fourier transform or a Fourier transform of the output signal, to provide a frequency spectrum of the optical signal.
Abstract:
A method for detecting trace evidence materials on a surface comprises irradiating the surface with radiation from two or more lasers emitting radiation at different wavelengths selected to stimulate luminescence in the trace materials. The evidence is detected by observing the surface through an optical filter arranged to transmit the luminescence, while blocking transmission of the laser radiation wavelengths reflected or scattered from the surface.