Abstract: A reconstruction technique for reducing computation burden in the 3D image processes, wherein the reconstruction procedure comprises an inverse and a forward model. The inverse model uses a hybrid dual Fourier algorithm that combines a 2D Fourier inversion with a 1D matrix inversion to thereby provide high-speed inverse computations. The inverse algorithm uses a hybrid transfer to provide fast Fourier inversion for data of multiple sources and multiple detectors. The forward model is based on an analytical cumulant solution of a radiative transfer equation. The accurate analytical form of the solution to the radiative transfer equation provides an efficient formalism for fast computation of the forward model.

Abstract: The Stokes shift emission spectra were measured for various samples, including tissues containing photoactive bio-molecules such as tryptophan, elastin, collagen, NADH and flavin. This new approach allows for the extraction of new information not easily obtained from the excitation and or fluorescence spectra of the same samples. For example, Stokes shift spectroscopy of tissue samples can detect disease states in humans and animals.

Abstract: The present invention provides systems and methods for non-destructively detecting material abnormalities beneath a coated surface. A terahertz (THz) illumination unit illuminates an area of the coated surface. A detection unit detects light reflected from the illuminated area of the coated surface, and a processing unit images the illuminated area of the coated surface from optical characteristics received from the detection unit.

Abstract: The design and operation of a p-i-n device, operating in a sequential resonant tunneling condition for use as a photodetector and an optically pumped emitter, is disclosed. The device contains III-nitride multiple-quantum-well (MQW) layers grown between a III-nitride p-n junction. Transparent ohmic contacts are made on both p and n sides. The device operates under a certain electrical bias that makes the energy level of the first excitation state in each well layer correspond with the energy level of the ground state in the adjoining well layer. The device works as a high-efficiency and high-speed photodetector with photo-generated carriers transported through the active MQW region by sequential resonant tunneling. In a sequential resonant tunneling condition, the device also works as an optically pumped infrared emitter that emits infrared photons with energy equal to the energy difference between the first excitation state and the ground state in the MQWs.

Abstract: A method of improving a signal-to-noise (S/N) ratio for a light signal transmitted by wireless optical communication through adverse environmental conditions, the light signal including a snake component and a ballistic component for carrying coded information, and a diffusive component that adds to background noise, the method comprising the steps of: encoding information to be transmitted by the light signal, wherein the light signal is one of a serial train of code pulses or a modulated light beam; selecting an appropriate wavelength for the encoded light signal; transmitting the encoded light signal though the adverse environmental conditions; receiving the encoded light signal; sorting the received encoded light signal to preferentially select the information carrying components and reduce the diffusive component; and detecting the sorted encoded light signal with a photo-detector.

Abstract: The present invention provides systems and methods for non-destructively detecting material abnormalities beneath a coated surface, comprising a mid-infrared (MIR) illumination unit for illuminating an area of the coated surface, and an MIR 2-D imager, which includes an MIR CCD or CMOS camera, for capturing an image of a material abnormalities under the illuminated area of the coated surface. In addition, the system may further comprise a scanning unit for moving the system to a next area.

Abstract: Laser tissue welding can be achieved using tunable Cr4+ lasers, semiconductor lasers and fiber lasers, where the weld strength follows the absorption spectrum of water. The use of gelatin and esterified gelatin as solders in conjunction with laser inducted tissue welding impart much stronger tensile and torque strengths than albumin solders. Selected NIR wavelength from the above lasers can improve welding and avoid thermal injury to tissue when used alone or with gelatin and esterified gelatin solders. These discoveries can be used to enhance laser tissue welding of tissues such as skin, mucous, bone, blood vessel, nerve, brain, liver, pancreas, spleen, kidney, lung, bronchus, respiratory track, urinary tract, gastrointestinal tract, or gynecologic tract and as a sealant for pulmonary air leaks and fistulas such as intestinal, rectal and urinary fistulas.

Abstract: The present invention provides systems and methods for non-destructively detecting material abnormalities beneath a coated surface, comprising a mid-infrared (MIR) detection unit for illuminating an area of the coated surface and detecting light reflected from the illuminated area of the coated surface, and a processing unit for producing an image from optical characteristics received from the MIR detection unit. In addition, the system may further comprise a scanning unit for moving the MIR detection unit to a next area.

Abstract: A system and method for exposing ocular tissue to a beam of electromagnetic radiation tuned to an NIR wavelength between about 1380 nm and about 1600 nm in the water absorption band. The laser energy is absorbed by the water, which in turn, transfers the energy to collagen molecules. The helical collagen molecules partially denature and then re-nature to form a weld across the region of the tissues to be joined. In a preferred embodiment, the electromagnetic radiation originates from a laser. The lasers may be Cr4+ doped crystals, Erbium fibers, and alloys of semiconductor laser diodes.

Abstract: The Stokes shift emission spectra were measured for various samples, including tissues containing photoactive bio-molecules such as tryptophan, elastin, collagen, NADH and flavin. This new approach allows for the extraction of new information not easily obtained from the excitation and or fluorescence spectra of the same samples. For example, Stokes shift spectroscopy of tissue samples can detect disease states in humans and animals.

Abstract: The design and operation of a p-i-n device, operating in a sequential resonant tunneling condition for use as a photodetector and an optically pumped emitter, is disclosed. The device contains III-nitride multiple-quantum-well (MQW) layers grown between a III-nitride p-n junction. Transparent ohmic contacts are made on both p and n sides. The device operates under a certain electrical bias that makes the energy level of the first excitation state in each well layer correspond with the energy level of the ground state in the adjoining well layer. The device works as a high-efficiency and high-speed photodetector with photo-generated carriers transported through the active MQW region by sequential resonant tunneling. In a sequential resonant tunneling condition, the device also works as an optically pumped infrared emitter that emits infrared photons with energy equal to the energy difference between the first excitation state and the ground state in the MQWs.

Abstract: A system and method for performing selected optical measurements on a sample is provided utilizing an optical coherence domain reflectometer which includes a diffraction grating. A broad band light source produces light having a short coherence length. A beamsplitter splits the light into a signal beam and a reference beam. A reference mirror is disposed to receive the reference beam. A lens brings the signal beam to focus on the sample. A diffraction grating receives reflections from the sample and from the reference mirror, the reflections being incident on the diffraction grating with respect to said diffraction grating normal such that a positive diffraction order from one of the reflections and a negative diffraction order from the other one of the reflections and a negative diffraction order from the other one of the reflections propagate along a common path.

Abstract: The present invention provides systems and methods for non-destructively detecting material abnormalities beneath a coated surface, comprising a mid-infrared (MIR) illumination unit for illuminating an area of the coated surface, and an MIR 2-D imager, which includes an MIR CCD or CMOS camera, for capturing an image of a material abnormalities under the illuminated area of the coated surface. In addition, the system may further comprise a scanning unit for moving the system to a next area.

Abstract: An apparatus for use in examining an object, such as skin, mucosa and cervical tissues for the purpose of detecting cancer and precancerous conditions therein. In one embodiment, the apparatus includes a gun-shaped housing having a handle portion and a barrel portion. The front end of the barrel portion is open, and a glass cover is mounted therein. Red, green, blue, and white LED's are disposed within the handle portion of the housing and are electrically connected to a battery also disposed within the handle portion of the housing. A manually-operable switch for controlling actuation of each of the four LED's is accessible on the handle portion of the housing. An optical fiber is disposed inside the housing and is used to transmit light from the four LED's through a first polarizer disposed in the barrel portion of the housing and then through the glass cover to illuminate a desired object.

Abstract: A method for imaging objects in a highly scattering turbid medium comprises: using a group of sources and detectors to generate a plurality of emergent energy waves from the medium, determining the intensity data of the emergent energy waves and processing the intensity data by using an image reconstruction algorithm. Arrangement of sources-detectors may be in parallel (transmission and/or backscattering) geometry or in cylinder geometry. The reconstruction algorithm is a novel hybrid dual Fourier tomographic algorithm for a fast 3D image reconstruction. The forward models are the radiative transfer model based on the cumulant solution of the radiative transfer equation or the diffusion model based on the approximate diffusion equation.

Abstract: Method and apparatus for imaging objects in turbid media. In one embodiment, the method comprises illuminating at least a portion of the turbid medium with substantially monochromatic light of at least two wavelengths in the 600-1500 nm spectral range. A first of the at least two wavelengths is equal to a resonance wavelength for an optical property of an object in the illuminated portion of the turbid medium but is not equal to a resonance wavelength for the turbid medium. A second of the at least two wavelengths is not equal to a resonance wavelength for either the object or the turbid medium. Light emergent from the turbid medium following each of the foregoing illuminations comprises a ballistic component, a snake component and a diffuse component. A direct shadowgram image may be obtained by preferentially passing from the emergent light, following each illumination. the ballistic and snake components thereof and detecting the preferentially passed light.

Abstract: Method and an apparatus for examining a tissue using the spectral wing emission therefrom induced by visible to infrared photoexcitation. In one aspect, the method is used to characterize the condition of a tissue sample and comprises the steps of (a) photoexciting the tissue sample with substantially monochromatic light having a wavelength of at least 600 nm; and (b) using the resultant far red and near infrared spectral wing emission (SW) emitted from the tissue sample to characterize the condition of the tissue sample. In one embodiment, the substantially monochromatic photoexciting light is a continuous beam of light, and the resultant steady-state far red and near infrared SW emission from the tissue sample is used to characterize the condition of the tissue sample.

Abstract: The present invention provides systems and methods for non-destructively detecting material abnormalities beneath a coated surface, comprising a mid-infrared (MIR) detection unit for illuminating an area of the coated surface and detecting light reflected from the illuminated area of the coated surface, and a processing unit for producing an image from optical characteristics received from the MIR detection unit. In addition, the system may further comprise a scanning unit for moving the MIR detection unit to a next area.

Abstract: A method for monitoring a biological tissue includes illuminating the tissue, including a fluorophore, with a wavelength of light, the wavelength selected for exciting the fluorophore, determining a fluorescent emission of the fluorophore, the emission indicating the presence of the fluorophore, and correlating an emission of the fluorophore to an extent and degree of damage to the tissue. Damage to the tissue includes a breakdown of the fluorophore, resulting in a reduced level of emission. The fluorophore can include one of collagen and elastin. The fluorophore can include tryptophan, nicotinamide adenine dinucleotide, flavin and porphyrin. Correlating the emission of the fluorophore to the extent and degree of damage further includes processing a correlation of the emission over time, controlling the power of a laser welder based on the processed correlation, and preventing overheating of the tissue by the laser welder.

Abstract: Method and apparatus for examining biological materials using diffuse reflectance spectroscopy and the Kubelka-Munk function. In one aspect, the method is used to determine whether a tissue sample is cancerous or not and comprises the steps of (a) measuring the diffuse reflectance from the tissue sample at a first wavelength and at a second wavelength, wherein the first wavelength is a wavelength selected from the group consisting of 255-265 nm and wherein the second wavelength is a wavelength selected from the group consisting of 275-285 nm; (b) using the Kubelka-Munk function to transform the diffuse reflectance measurement obtained at the first and second wavelengths; and (c) comparing a ratio or a difference of the transformed Kubelka-Munk measurements at the first and second wavelengths to appropriate standards determine whether or not the tissue sample is cancerous.