USA As Represented by Secretary of the Navy

Mark Bashkansky

John F Reintjes

Michael D Duncan

Adam T Black

Ronald W Waynant

Lawrence L Tankersley

Rita Mahon

Bernard L Wexler

Samuel Park

Matthew Terraciano

Fredrik K Fatemi

Jonathan Kwolek

Charles Fancher

A method for using a single-pixel camera to reconstruct images of objects obscured by fog or other dynamic scattering media. A pseudo-random phase or intensity pattern is imposed on illumination beams directed at a target. The beam with the imposed pattern forms a pseudo random pattern on the target. Information regarding the pattern imposed on each pulse is entered into a data processor/controller. The illumination beams with the pseudo random patterns are reflected off the target, collected by receiving optics and a bucket detector and converted into electronic signals fed into the data processor/controller. The data processor/controller applies a high-pass filter to remove slower signal variations produced by dynamic changes in the scattering medium over time. The filtered bucket values are then used together with their corresponding speckle patterns to generate the images using any appropriate reconstruction algorithm such as CGI or CSI.

Single-pixel imaging through dynamic scattering media

Method and apparatus for producing a cooled atom beam suitable for use applications requiring cold atoms. A two-stage cooling process is employed in which the atoms in the atom beam are cooled in two, spatially separated regions of a cooling apparatus, wherein the atoms are first cooled in two dimensions by two counterpropagating laser beams under a magnetic field and then are cooled in three dimensions by means of an optical molasses, where the power, frequency, and magnetic fields are tuned to obtain a continuous beam of three-dimensionally cooled atoms having a controllable velocity distribution, very low decoherence, and low background atomic gas loss.

Continuous, velocity-controlled three-dimensionally laser-cooled atom beam source with low fluorescence

A method and system for remotely imaging a magnetic field within an atom cloud is provided. An atom sample held in a magneto-optical trap is released, and the released atom cloud is illuminated by a Raman beam. Resonant atoms having certain velocities will absorb photon momenta from the Raman beam. The velocities of those resonant atoms will change in response to the absorbed momenta, causing a change in the travel distance of those atoms as compared with non-resonant atoms. The atom cloud is imaged by an imaging device such as a CCD camera and the presence of the resonant atoms is shown in the images as bright lines in the atom cloud. The distance traveled by the resonant atoms and therefore the separation of the lines in the image is a function of the magnetic fields in the atom cloud. The system and method of the present invention can image the magnetic fields within an atom cloud with a high spatial resolution over the entire atom cloud in a single imaging cycle, and analysis of the image provides information regarding the magnetic fields.

Single-shot spatially-resolved imaging magnetometry using ultracold atoms

A method and apparatus for reducing speckle due to MSL, without any loss of resolution, by averaging over different angles of the incident light at low input resolution, while collecting the backscattered light at a full resolution of a lens is described. The present invention allows discrimination against the speckle due to coherent MSL.

Method and apparatus for reducing speckle in optical coherence tomography images

A scanning system for scanning in first and second dimensions a desired surface topology of a sample, the scanning device comprising: a light source for producing a collimated light beam; a first scanning device responsive to the collimated light beam from the light source for producing a first scanned beam in a first dimension with a constant optical path length; and a second scanning device coupled between the first scanning device and the sample for focusing and scanning the first scanned beam in a second dimension onto the surface region of the sample to cause the collimated light beam to scan the surface topology of the sample with a constant optical path length in each of the first and second dimensions of the desired topology of the sample. In a second embodiment of the invention, a beam of light is focused by a first lens before a scanner and the scanner is rotated. Second and third lenses arranged in a 4-f combination are used to image rotated focal spots along a spherical convex surface of a sample while the optical path length stays constant. Slow scanning in other dimensions can be performed by mechanical means.

Rapid, high-resolution scanning of flat and curved regions for gated

An apparatus for imaging through scattering materials produces a broadband laser reference beam and a correlated Stokes illumination beam. The broadband reference beam has a preselected Raman pump wavelength and the Stokes illumination beam has a preselected Stokes wavelength. The Stokes illumination beam is transmitted into the scattering material to obtain a Stokes signal beam having a first image carrying component and a first nonimage component. A relative delay is produced between the reference beam and the Stokes signal beam. The delayed reference beam and the delayed Stokes signal beam are polarized. The polarized reference beam and the polarized Stokes signal beam are combined to produce a combined beam having a Stokes component and a reference component, the Stokes component having a second image carrying component and a second nonimage component, so that the second image carrying component and the reference component are mutually correlated, and so that the polarization state of the Stokes component differs from the polarization state of the reference component. A Stimulated Raman amplifier responsive to the combined beam produces an amplified signal beam having a third image carrying component with polarization state perpendicular to the polarization state of the Stokes component and having a third nonimage component with polarization state parallel to the polarization state of the Stokes component. The third image carrying component is separated from the rest of the amplified signal beam with the use of a polarizer and is later detected.

Time gated imaging through scattering material using polarization and

A method and apparatus for imaging an object that is part of, embedded in or viewed through a scattering medium is provided. A first broadband beam generator, such as a broadband pulse laser, provides a first broadband beam. A second broadband beam generator, such as a Raman Stokes generator disposed to receive the first broadband beam, generates a second broadband beam capable of correlation with the first broadband beam. A coherent anti-Stokes Raman scattering material is disposed to receive the second broadband beam after dispersion in the scattering medium. A variable delay path also illuminates the coherent anti-Stokes Raman scattering material with the first broadband beam. The coherent anti-Stokes Raman scattering material produces an anti-Stokes beam which contains an extracted image of an object in the scattering medium, which image is recorded on a photodetector.

Apparatus for imaging an object in or through a scattering medium using

A pulse discharge laser is provided having a pair of electrodes disposed within a laser chamber pressurized with a high-pressure gas. A preionizer generator intermittently produces preionization energy to preionize the high pressure gas in the laser chamber. A pulse forming network intermittently supplies a ramping voltage to the pair of electrodes. When the high pressure gas in the laser chamber is not properly preionized by the preionization energy a damaging arc may occur and lasing will not occur by discharge of the ramping voltage on the electrodes. A passive electrode arc protector is provided connected across the pair of laser electrodes to discharge the ramping voltage across the electrodes when the high pressure gas is not properly preionized to protect the laser electrodes from a damaging arc between them.

Pulse discharge laser with passive arc protection

An apparatus for the time-gated optical examination of objects that are p of, embedded in or viewed through dense scattering materials is disclosed. In a preferred embodiment, the apparatus comprises: a light source for producing a first light pulse and a pump light pulse, each of the first and pump light pulses having a preselected pulse width at a preselected pump wavelength; a Raman generator for shifting the wavelength of the first light pulse to a preselected Stokes wavelength to form Stokes light; a first optical train for transmitting the Stokes light through the dense scattering material to obtain Stokes light comprised of a relatively small, image-bearing signal component including unscattered Stokes light or Stokes light with minimal deviation due to scattering, light followed in time by a relatively large amount of light scattered by the dense scattering material; a Raman amplifier; an optical system for transporting the Stokes light from the dense scattering material to the Raman amplifier; a variable delay path disposed between the light source and the Raman amplifier for varying the transit time of the pump pulse to cause the pump pulse to overlap in time with the signal component of Stokes light at the Raman amplifier, the Raman amplifier only amplifying the signal component of Stokes light that is overlapped in time by the pump pulse; and a two-dimensional detector for detecting the amplified signal component of Stokes light.

Time-gated imaging through dense-scattering materials using stimulated

A method and apparatus for imaging an object that is part of, embedded in, or viewed through a scattering medium is provided. A broadband stochastic beam generator, such as a broadband laser, generates a broadband stochastic beam and a narrowband beam generator generates a narrowband beam. A non-linear mixing crystal receives the broadband stochastic beam and the narrowband beam and provides a signal light beam conjugate correlated with the broadband stochastic beam to the scattering medium. A multiple-wave mixing cell is disposed to receive the signal light beam from the scattering medium. An adjustable delay path also illuminates the multiple-wave mixing cell with the broadband stochastic beam. A supplemental beam generator is also provided for also additionally illuminating the multiple-wave mixing cell with a supplemental beam having characteristics sufficient to satisfy phase matching with the material of the multiple-wave mixing cell. The multiple-wave mixing cell produces an image-bearing beam which contains an image of an object extracted from the signal light beam emitted from the scattering medium. The apparatus can further include a detector to record the image of the object in the image-bearing beam.

Growing community of inventors

Alexandria, VA, United States of America

Mark Bashkansky