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: 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 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: 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: 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 multiple-stage optical Kerr gate system for gating a probe pulse of light. In a first embodiment, the system includes at least two optical Kerr gates, each Kerr gate including a polarizer, an optical Kerr cell actuable by a pump pulse, and an analyzer. In a second embodiment, at least one of the Kerr cells may be eliminated by arranging the respective sets of polarizers and analyzers so that they share a common Kerr cell. Gated pulses obtained using the present system typically have a signal to noise ratio that is at least 500 times better than that for gated pulses obtained using a single optical Kerr gate system. The system of the present invention may also include means for causing the pump pulse to arrive at the second Kerr cell (in the case of the first embodiment) or at a single Kerr cell a second time (in the case of the second embodiment) non-synchronously with the arrival of the probe pulse thereat.

Abstract: A method for detecting the presence of one or more calcifications within a portion of a turbid medium, such as a breast tissue. According to one aspect, the method involves illuminating at least a portion of the turbid medium with light, whereby light emerges from the turbid medium consisting of a ballistic component, a snake-like component and a diffuse component, temporally and/or spatially gating the emergent light to preferentially pass the ballistic and/or snake-like components, using the temporally and/or spatially gated light to form an image of the illuminated portion of the turbid medium, and examining the image for the presence of one or more calcifications. Wavelength difference images may also be used to highlight tumors and calcification regions.

Abstract: A method for amplifying a signal pulse of laser light. Preferably, the method is used to amplify 1.3 .mu.m and/or 1.55 .mu.m signal pulses emitted from any 1.3 .mu.m or 1.55 .mu.m signal source, the method comprising providing an amplifying medium, the amplifying medium comprising an elongated core and a light-retaining outer structure surrounding the elongated core. The elongated core preferably comprises a plurality of Cr.sup.4+ -doped crystalline particles capable of lasing at 1.3 .mu.m and/or 1.55 .mu.m and preferably having a size of approximately 0.05 .mu.m to 500 .mu.m. The crystalline particles are dispersed within a non-gaseous medium, the non-gaseous medium having an index of refraction that substantially matches that of the crystalline particles.

Abstract: A method of forming 2 dimensional image of a translucent object in or behind a turbid medium. In one embodiment, the method comprises the steps of illuminating the translucent object through one side of the turbid medium with an ultrafast pulse of light, the light emergent from the opposite side of the turbid medium consisting of a ballistic component, a snake-like component and a diffuse component. The emergent light is then temporally and spatially gated to preferentially pass the ballistic component and the snake-like component. Preferably, the temporal and spatial gating is achieved by positioning the Kerr cell of an optical Kerr gate at the 2F spectral plane of a 4F Kerr-Fourier imaging system. At the appropriate time, that portion of the Kerr cell located at the focal point of the 2F spectral plane is gated open, allowing predominantly ballistic and snake-like components of the transilluminated light to pass therethrough.

Abstract: An optical streak camera includes an optical collimator, an all optical deflector, a detector and a display.

Abstract: Optical communication systems, optical computing systems and optical logic elements which rely on the phenomina of cross-phase modulation to alter and control, either or simultaneously, the spectral, temporal or/and spatial properties of ultrashort light pulses for processing information with high speed repetition rates. A weak beam of ultrashort light pulses is modulated by an intense beam of ultrashort light pulses by copropagating both beams through a non-linear medium such that cross-phase modulation effects are realized.

Abstract: Optical communication systems, optical computing systems and optical logic elements which rely on the phenomina of cross-phase modulation to alter and control, either or simultaneously, the spectral, temporal or/and spatial properties of ultrashort light pulses for processing information with high speed repetition rates. A weak beam of ultrashort light pulses is modulated by an intense beam of ultrashort light pulses by copropagating both beams through a non-linear medium such that cross-phase modulation effects are realized.

Abstract: A system for imaging an object in or behind a highly scattering medium includes a laser for illuminating the highly scattering medium with a beam of light. The light emerging from the highly scattering medium consists of a ballistic component, a snake-like component and a diffuse component. A 4F Fourier imaging system with a Kerr gate located at 2F is used to form a time-space gated image of the emerging light, the time-space gated image consisting primarily of the ballistic component and the snake-like component.

Abstract: A multiple-stage optical Kerr gate system for gating a probe pulse of light. In a first embodiment, the system includes at least two optical Kerr gates, each Kerr gate including a polarizer, an optical Kerr cell actuable by a pump pulse, and an analyzer. In a second embodiment, at least one of the Kerr cells may be eliminated by arranging the respective sets of polarizers and analyzers so that they share a common Kerr cell. Gated pulses obtained using the present system typically have a signal to noise ratio that is at least 500 times better than that for gated pulses obtained using a single optical Kerr gate system. The system of the present invention may also include means for causing the pump pulse to arrive at the second Kerr cell (in the case of the first embodiment) or at a single Kerr cell a second time (in the case of the second embodiment) non-synchronously with the arrival of the probe pulse thereat.

Abstract: Optical communication systems, optical computing systems and optical logic elements which rely on the phenomena of cross-phase modulation to alter and control, either or simultaneously, the spectral, temporal or/and spatial properties of ultrashort light pulses for processing information with high speed repetition rates. A weak beam of ultrashort light pulses is modulated by an intense beam of ultrashort light pulses by copropagating both beams through a non-linear medium such that cross-phase modulation effects are realized.

Abstract: An apparatus for producing a 3-dimensional image of semi-transparent object or of a opaque object in a semi-transparent media includes a picosecond or a femtosecond laser, a streak camera, a coherent fiber bundle, a video camera and a computer. The apparatus provides a unique nondestructive and non-invasive diagnostic way for detecting, for example, objects hidden in semi-opaque media. The laser is used to produce an ultrashort light pulse. The coherent fiber bundle is used to convert the 2-dim spatial image that is produced (i.e. scattered or fluorescence light from a 3-dim object illuminated with the ultrashort laser pulse) into a 1-dim line image which is fed into the input slit of the streak camera and then time resolved by the streak camera. The video camera is used to record the 2-dim output (1-dim from input image and 1-dim of the streak time) from the streak camera. The output of the video camera is fed into the computer.

Abstract: An apparatus for determining and displaying the time evolution profile of electron carriers present within a submicron or micron device comprises a laser for generating a beam of ultrafast pulses of ultraviolet light. A first beam splitter splits each pulse into a transmitted beam and a reflected beam. The transmitted beam travels through a time delay circuit, and is then converted into a train of ultrafast electrical pulses which are transmitted to the device. The reflected beam is focused on the device. An electron detector, also focused on the device, collects the ejected electrons resulting from the interaction of the light pulse and electrical pulse to produce an electrical signal. The signal is then magnified in intensity by an amplifier and directed at a cathode ray tube to cause an image to appear thereon. A SIT vidicon camera converts the image into an electrical signal and transmits the signal to a computer.

Abstract: A method for producing a phase hologram having a high diffraction efficiency which includes treating a developed photographic material with a stop bath containing sodium sulfate, bleaching with a tanning bleach having a low pH value and fixing the bleached material in a bath containing sodium thiosulfate.