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 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: A method and system for examining biological materials using low-power cw excitation Raman spectroscopy. A low-power continuous wave (cw) pump laser beam and a low-power cw Stokes (or anti-Stokes) probe laser beam simultaneously illuminate a biological material and traverse the biological material in collinearity. The pump beam, whose frequency is varied, is used to induce Raman emission from the biological material. The intensity of the probe beam, whose frequency is kept constant, is monitored as it leaves the biological material. When the difference between the pump and probe excitation frequencies is equal to a Raman vibrational mode frequency of the biological material, the weak probe signal becomes amplified by one or more orders of magnitude (typically up to about 104-106) due to the Raman emission from the pump beam.

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: 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: A system for non-destructively imaging surfaces through a coating, in accordance with the present invention, includes a near-infrared (NIR) light source for illuminating a coated surface. A detector is positioned in an operative relationship with the NIR light source to receive light backscattered from the coated surface and from the coating. A gating device is positioned in an operative relationship with the detector to selectively permit light to pass to the detector to measure optical characteristics of the backscattered light such that determinations of a state of a surface below the coating is determined based on the optical characteristics of the backscattered light. Methods for performing the non-destructive imaging of the present invention are also disclosed.

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: A system to detect eye disease in which monochromatic laser light is directed into the vitreous humor after passing through the front of the eye. A very sensitive detection system then detects the light scattered from the vitreous humor as it exits the eye. The light is scattered at a wavelength different from that of the laser in a manner known as Raman scattering. The wavelength of the Raman scattered photons are shifted by vibrational modes of the molecules, and this shift is a characteristic feature of the molecules interacting with the light. In this way, the Raman scattered light is essentially imprinted with a fingerprint of relevant molecules. As it exits the eye, this Raman scattered light can be separated from other types of scattered light and then routed to a detection system, wherein the results are calibrated against actual standards for the particular vitreous substances being analyzed.

Abstract: A photon-mediated technique for introducing biological materials into cells and/or cellular components. The technique may be used to introduce nucleic acids, such as DNA and RNA, proteins or other biological materials into mammalian cells (as well as into other animal and plant cells), which materials may then flow into the nuclei of the cells. The technique uses picosecond or femtosecond light pulses propagating in the UV, visible and near infrared wavelength regions with powers on the order of 1×1010 W/cm2. In practice, the desired biological materials are coated on the end of the inner core of a single mode fiber or the ring core of a fiber in a fiber array. Each fiber is sized to correspond to one cell, with the core size ranging from 2&mgr; to 10&mgr;, and the cladding ranging from 10&mgr; to 30&mgr;. The laser pulse travels through a fiber core which is coated with the materials and ablates a portion of a targeted cell or cellular component membrane.

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: 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: Imaging of objects within tissue is enhanced by applying a contrast agent to a sample to be imaged to augment the emissions from an object, thereby forming a luminous object. The tissue is then illuminated and two image signals are recorded. The contrast agent is selected to bind to the object and provide spectral characteristics significantly different from that of the tissue for the two recorded image signals. The two image signals are subtracted to substantially minimize an image component resulting from the tissue and enhance an image component from the luminous object. The imaging methods and apparatus are particularly well suited for medical imaging where the object is diseased tissue such as tumors.

Abstract: Remote-controllable, micro-scale, robotic device for use in diagnosing and/or treating abnormalities inside a human body in vivo. The device has a length from 0.1 mm to 10 mm and can be introduced into the body either from natural body openings or by injection into the blood stream. Once inside the body, the device can be guided to different locations in the body by an outside operator using radio controls and computer software. 2-dimensional image information and spectroscopic information (e.g., fluorescence, absorption, elastic scattering, Raman, etc.) gathered by the device inside the body are transmitted by video and radio signals to a computer located externally relative to the body. The transmitted information is processed, analyzed and displayed by the external computer for use by the outside operator. The outside operator can then make a diagnosis and, if applicable, instruct the device to render a treatment on the examined area.

Abstract: A method and system for imaging a small object in or behind a highly scattering medium comprises a laser source for illuminating the object with an ultrashort collimated beam of light and a novel microscope for forming a magnified image of the object using light emergent from the highly scattering medium, the emergent light consisting of a scattered component and a non-scattered component. The novel microscope comprises an objective, an eyepiece and an aperture centered at the back focal plane of the objective. The aperture, which may be of a fixed or variable size and controlled electronically or by a computer serves to spatially filter the scattered light component of the light emergent from the highly scattering medium. The system may also comprise a streak camera or similar time resolving device positioned at the image plane of the microscope for temporally filtering the scattered light component of the light emergent from the highly scattering medium.

Abstract: An apparatus utilizing non-linear optical signals for use in constructing a three-dimensional tomographic map of an in vivo biological tissue for medical disease detection purposes. In one embodiment, said apparatus comprises a stage for supporting the in vivo biological tissue; a laser for illuminating the in vivo biological tissue with a focused beam of laser light, the light emerging from the in vivo biological tissue comprising fundamental light, harmonic wave light, and fluorescence due to multi-photon excitation; a filter for selectively passing only at least one of the harmonic wave light and the fluorescence; one or more detectors for individually detecting each of the harmonic wave light and the fluorescence selectively passed; and a mechanism for moving the laser relative to the stage in x, y and z directions.

Abstract: A method and system for examining biological materials using low-power cw excitation Raman spectroscopy. In accordance with the teachings of the invention, a low-power continuous wave (cw) pump laser beam and a low-power cw Stokes (or anti-Stokes) probe laser beam simultaneously illuminate a biological material and traverse the biological material in collinearity. The pump beam, whose frequency is varied, is used to induce Raman emission from the biological material. The intensity of the probe beam, whose frequency is kept constant, is monitored as it leaves the biological material. When the difference between the pump and probe excitation frequencies is equal to a Raman vibrational mode frequency of the biological material, the weak probe signal becomes amplified by one or more orders of magnitude (typically up to about 10.sup.4 -10.sup.6) due to the Raman emission from the pump beam.

Abstract: A method for imaging objects in highly scattering turbid media. According to one embodiment of the invention, the method involves using a plurality of intersecting source/detectors sets and time-resolving equipment to generate a plurality of time-resolved intensity curves for the diffusive component of light emergent from the medium. For each of the curves, the intensities at a plurality of times are then inputted into the following inverse reconstruction algorithm to form an image of the medium: wherein W is a matrix relating output at source and detector positions r.sub.s and r.sub.d, at time t, to position r, .LAMBDA. is a regularization matrix, chosen for convenience to be diagonal, but selected in a way related to the ratio of the noise, <nn>to fluctuations in the absorption (or diffusion) X.sub.j that we are trying to determine:.LAMBDA..sub.ij =.lambda..sub.j .delta..sub.ij with .lambda..sub.j =<nn>/<.DELTA.Xj.DELTA.Xj>Y is the data collected at the detectors, and X.sup.

Abstract: A method and system for imaging an object in a turbid medium. According to one embodiment, the method involves (a) making the object luminescent by adding to the object a contrast agent of the type that emits at least partially polarized light when appropriately excited with polarized radiation; (b) exciting the luminescent object through the turbid medium with polarized radiation so as to cause luminescent light to be emitted from the luminescent object, the luminescent light initially being at least partially polarized; (c) after the luminescent light has emerged from the turbid medium, the luminescent light consisting of a ballistic component, a snake-like component and a diffuse component, detecting a pair of complementary polarization components of the luminescent light; and (d) forming an image of the object using the pair of complementary polarization components.

Abstract: A method of detecting cancer or precancerous conditions in a tissue or cell using fluorescence excitation spectroscopy. According to one embodiment of the method, a tissue is tested for cancer or a precancerous condition by exciting the tissue with substantially monochromatic light at 268 nm and then at 289 nm, with the resultant native fluorescence emitted from the tissue following each excitation being measured. A ratio of the fluorescence intensities, e.g., I.sub.289 /I.sub.268, is then calculated. If I.sub.289 /I.sub.268 is greater than 1.5, the tissue is cancerous or precancerous whereas if I.sub.289 /I.sub.268 is less than 1.5, the tissue is not cancerous or precancerous.

Abstract: A method and apparatus for examining a cell smear for the purpose of detecting the presence of cancerous and precancerous cells located therein. In a preferred embodiment, the method comprises illuminating at least a portion of the cell smear with light of a first wavelength, whereby native fluorescence is emitted therefrom. Next, the intensity of native fluorescence emitted from the illuminated area is measured at a second wavelength and at a third wavelength as a function of location within the illuminated area. The first, second and third wavelengths are chosen so that the ratio of fluorescence intensities at the second and third wavelengths is indicative of a carcinomatous condition. Next, the ratio of intensities measured at the second and third wavelengths is determined to obtain a value for each location within the illuminated area. Finally, a map is generated of all the cells present within the illuminated area using the calculated values.