1. Massachusetts Institute of Technology

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    1. Mentioned In 531 Articles

    2. Identification and verification using complex, three-dimensional structural features

      Three-dimensional characteristics of a complex physical structure are used to generate a unique identifier. In effect, the characteristics reperesent the basis of a "physical one-way hash function" that faciliates ready derivation of an identifier based on the physical structure, the structure itself being very difficult to reproduce given only the identifier. The characteristics may be read using a non-contact probe and without the need for precise registration.
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    3. Fiber optic needle probes for optical coherence tomography imaging

      Fiber optic needle probes for optical coherence tomography imaging
      A fiber optic needle probe for measuring or imaging the internal structure of a specimen includes a needle defining a bore, an optical fiber substantially positioned within the bore, and a beam director in optical communication with the optical fiber. At least a portion of the wall of the needle is capable of transmitting light. The beam director directs light from the optical fiber to an internal structure being imaged ...
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    4. Fiber optic imaging endoscope interferometer with at least one faraday rotator

      Fiber optic imaging endoscope interferometer with at least one faraday rotator
      An imaging system for performing optical coherence tomography includes an optical radiation source; a reference optical reflector; a first optical path leading to the reference optical reflector; and a second optical path coupled to an endoscopic unit. The endoscopic unit preferably includes an elongated housing defining a bore; a rotatable single mode optical fiber having a proximal end and a distal end positioned within and extending the length of the ...
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    5. Methods and apparatus for forward-directed optical scanning instruments

      Methods and apparatus for forward-directed optical scanning instruments
      An imaging system for performing forward scanning imaging for application to therapeutic and diagnostic devises used in medical procedures. The imaging system includes forward directed optical coherence tomography (OCT), and non-retroreflected forward scanning OCT. Also interferometric imaging and ranging techniques and fluorescent, Raman, two-photon, and diffuse wave imaging can be used. The forward scanning mechanisms include a cam attached to a motor, pneumatic devices, a pivoting device, piezoelectric transducers, electrostatic ...
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    6. Interferometeric imaging with a grating based phase control optical delay line

      An apparatus for performing high speed scanning of an optical delay and its application for performing optical interferometry, ranging, and imaging, including cross sectional imaging using optical coherence tomography, is disclosed. The apparatus achieves optical delay scanning by using diffractive optical elements in conjunction with imaging optics. In one embodiment a diffraction grating disperses an optical beam into different spectral frequency or wavelength components which are collimated by a lens ...
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    7. Intraluminal fiber-optic Doppler imaging catheter for structural and functional optical coherence tomography

      We describe a miniature fiber-optic Doppler imaging catheter for integrated functional and structural optical coherence tomography (OCT) imaging. The Doppler catheter can map blood flow within a vessel as well as image vessel wall structures. A prototype Doppler catheter has been developed and demonstrated for measuring the intraluminal velocity profile in a vessel phantom (conduit). A simple mathematical model is demonstrated to estimate the total flow rate. This estimation technique ...
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    8. Grating based phase control optical delay line

      An apparatus for performing high speed scanning of an optical delay and its application for performing optical interferometry, ranging, and imaging, including cross sectional imaging using optical coherence tomography, is disclosed. The apparatus achieves optical delay scanning by using diffractive optical elements in conjunction with imaging optics. In one embodiment a diffraction grating disperses an optical beam into different spectral frequency or wavelength components which are collimated by a lens ...
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    9. Method and apparatus for arbitrary spectral shaping of an optical pulse

      A method and an apparatus for stretching an optical pulse and shaping its spectrum. The method includes the step of: providing a an optical fiber element having a first long length fiber Bragg grating having a refractive index perturbation of varying periodicity. The optical pulse is launched into the fiber Bragg grating, wherein the Bragg grating reflects the pulse in a chromatically dispersed output. The reflected output is coupled with ...
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    10. Method and apparatus for performing optical frequency domain reflectometry

      Method and apparatus for performing optical frequency domain reflectometry
      Method of performing OFDR on a sample comprising steps of: providing an external-cavity frequency-tuned laser having an optical cavity of effective length; tuning the laser to generate a change in wavelength; changing the effective length of the optical cavity proportionally to the change in wavelength so as to tune the longitudinal cavity mode frequency at the same rate as the wavelength is changed; directing light from the laser onto the ...
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    11. Method and apparatus for performing optical measurements using a fiber optic imaging guidewire, catheter or endoscope

      Method and apparatus for performing optical measurements using a fiber optic imaging guidewire, catheter or endoscope
      An imaging system for performing optical coherence tomography includes an optical radiation source; a reference optical reflector; a first optical path leading to the reference optical reflector; and a second optical path coupled to an endoscopic unit. The endoscopic unit preferably includes an elongated housing defining a bore; a rotatable single mode optical fiber having a proximal end and a distal end positioned within and extending the length of the ...
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    12. Imaging needle for optical coherence tomography

      Imaging needle for optical coherence tomography
      We describe a miniature optical coherence tomography (OCT) imaging needle that can be inserted into solid tissues and organs to permit interstitial imaging of their internal microstructures with micrometer scale resolution and minimal trauma. A novel rotational coupler with a glass capillary tube is also presented that couples light from a rotating single-mode fiber to a stationary one. A prototype needle with a 27-gauge 410-mm outer diameter has been developed ...
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    13. Grating based phase control optical delay line

      An apparatus for performing high speed scanning of an optical delay and its application for performing optical interferometry, ranging, and imaging, including cross sectional imaging using optical coherence tomography, is disclosed. The apparatus achieves optical delay scanning by using diffractive optical elements in conjunction with imaging optics. In one embodiment a diffraction grating disperses an optical beam into different spectral frequency or wavelength components which are collimated by a lens ...
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    14. Three-dimensional light absorption spectroscopic imaging

      An absorption imaging spectrometer for providing a three-dimensional spectral image of a light-transmitting sample. Temporally incoherent light is used to illuminate the sample, with a portion of the beam split off as a reference beam and subsequently recombined with the return beam from the sample after a variable delay path. An optical configuration is provided for modulating a time delay of the reference beam, with the interferogram obtained at each ...
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    15. 496-510 of 531 « 1 2 ... 31 32 33 34 35 36 »
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  2. About Massachusetts Institute of Technology

    Massachusetts Institute of Technology

    Massachusetts Institute of Technology (MIT) is a private, coeducational research university located in Cambridge, Massachusetts. MIT has five schools and one college, containing 32 academic departments, with a strong emphasis in theoretical, applied, and interdisciplinary scientific and technological research.  Laser Medicine and Medical Imaging Group at MIT.  The RLE Laser Medicine and Medical Imaging Group and its close collaborators were the originators of optical coherence tomography (OCT), a diagnostic technology now used in a growing number of medical fields. The group currently works to further understand and exploit the capabilities of OCT technology, with ongoing investigations in topics related to optical coherence microscopy development and optical biopsy using OCT.