Other

City College of New York

Research Foundation of Cuny

Ping-Pei Ho

Robert R Alfano

Patrice Baldeck

Leming M Wang

Xiangchun Liang

Quan Z Wang

Lina Yang

Pierre A Galland

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.

Sub-surface imaging under paints and coatings using early light spectroscopy

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. In this manner, gated pulses may be obtained that are much shorter in duration than pulses gated with a single optical Kerr gate system.

Multiple-stage optical Kerr gate system

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. The foregoing method may be used to form optical images of breast tissues, with the presence in such images of calcifications suggestive of cancer being used to identify the corresponding breast tissues as good candidates for biopsy and screening for tumors.

Optical imaging of breast tissues to enable the detection therein of

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. A cooled CCD detector is positioned at the 4F spectral plane to form a 2-dimensional image of the temporally and spatially gated light.

2-dimensional imaging of translucent objects in turbid media

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

Apparatus using optical deflection

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.

Terahertz repetition rate optical computing systems, and communication

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.

Ultrafast optical imaging of objects in a scattering medium

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.

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. In the computer 2-dim data elements are reconstructed into a 3-dim image and then displayed on a monitor. This apparatus essentially converts a streak camera into the equivalent of a framing camera with continuous time imaging capability.

Three-dimensional optical imaging of semi-transparent and opaque objects

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. The computer generates a time evolution profile from the signal received which is sent to a monitor for display.

Growing community of inventors

Douglaston, NY, United States of America

Ping-Pei Ho