Massachusetts Institute of Technology

United States of America As Represented by the Secretary of the Air Force

Thomas H Jeys

Antonio Sanchez-Rubio

Ronald H Hoffeld

Vincenzo Daneu

William D Herzog

Jonathan Z Lin

Nicholas M F Judson

George S Haldeman

Alexander Stolyarov

Ryan Sullenberger

Brian G Saar

Shawn Michael Redmond

David Crompton

Tso Yee Fan

Robert K Reich

Gregory G Cappiello

Richard M Osgood, Iii

Richard J Molnar

Shane M Tysk

David L Spears

Jinendra K Ranka

Antonio Sanchez

Alexander M Stolyarov

A device, and corresponding method, can include a pump light source configured to irradiate a target specimen. The device can also include a sensor configured to observe a probe speckle pattern based on light from a probe light source reflected from the target specimen. The device further may include a correlator configured to determine a material property of the target specimen by analyzing changes in images of the probe speckle pattern as a function of the irradiation with the pump light source. Advantages of the device and method can include much higher sensitivity than existing methods; the ability to use visible probe wavelengths for uncooled, low-cost visible detectors with high spatial resolution; and the ability to obtain target material properties without detecting infrared light.

Material property determination using photothermal speckle detection

A device, and corresponding method, can include a pump light source configured to be modulated at a pump modulation and to irradiate a target specimen. The device can also include a probe light source arranged to generate a speckle pattern from the target specimen, as well as a sensor configured to detect changes in at least one of position and intensity of one or more speckle lobes of the speckle pattern having correlation with the pump modulation. The device and method can be used for non-contact monitoring and remote sensing of surfaces, gases, liquids, particles, and other target materials by analyzing speckle pattern changes as a function of pump light irradiation. Advantages can include much higher sensitivity than existing methods; the ability to use visible probe wavelengths for uncooled, low-cost visible detectors with high spatial resolution; and the ability to obtain target material properties without detecting infrared light.

Devices and methods for sensing targets using photothermal speckle detection

A method and an apparatus of measuring a position of a particle in a flow are disclosed. An embodiment of the method comprises temporally modulating and spatially pattering an illumination beam propagating along a first dimension, passing a particle across the modulated illumination beam, detecting a temporal profile of scattered light produced by the particle's passing through the modulated illumination beam, and determining the position of the particle based, in part, on the temporal profile of the detected scattered light.

Method and apparatus for measuring a position of a particle in a flow

Aerosol and hydrosol particle detection systems without knowledge of a location and velocity of a particle passing through a volume of space, are less efficient than if knowledge of the particle location is known. An embodiment of a particle position detection system capable of determining an exact location of a particle in a fluid stream is discussed. The detection system may employ a patterned illuminating beam, such that once a particle passes through the patterned illuminating beam, a light scattering is produced. The light scattering defines a temporal profile that contains measurement information indicative of an exact particle location. However, knowledge of the exact particle location has several advantages. These advantages include correction of systematic particle measurement errors due to variability of the particle position within the sample volume, targeting of particles based on position, capture of particles based on position, reduced system energy consumption and reduced system complexity.

A particle detection system that images and detects particles in a fluid flow stream through use of detector array(s) is described. The detection system may include light source arrays that may selectively illuminate a particle in a fluid stream. The detection system may also include a detector array employing smart binning to read the measured signals. The smart binning of the detector array may be achieved through knowledge of an exact particle location provided by a position sensitive detector. The detector array(s) may be low cost based on intelligence built into the system. This particle detection system may be particularly useful for detection and discrimination of different particle types since the read-out of the particle signals can be accomplished with low noise and can be flexible enough to optimize the read out measurements for each particle. The particle detection system may be used, for example, in early warning contamination detection systems and manufacturing processes.

Method and apparatus for detecting and discriminating particles in a fluid

Particle detection systems without knowledge of a location and velocity of a particle passing through a volume of space, are less efficient than if knowledge of the particle location is known. An embodiment of a particle position detection system capable of determining an exact location of a particle in a fluid stream is discussed. The detection system may employ a patterned illuminating beam, such that once a particle passes through the various portions of the patterned illuminating beam, a light scattering is produced. The light scattering defines a temporal profile that contains measurement information indicative of an exact particle location. However, knowledge of the exact particle location has several advantages. These advantages include correction of systematic particle measurement errors due to variability of the particle position within the sample volume, targeting of particles based on position, capture of particles based on position, reduced system energy consumption and reduced system complexity.

Method and apparatus for simultaneously measuring a three dimensional position of a particle in a flow

Biological aerosols are detected in real time by passing air, which may contain the aerosols, through a duct having a pair of photodetectors adjacent the duct for detecting fluorescence of the aerosols produced by ultraviolet laser beam illumination of the airflow. A pair of opposed mirrors, make the effective sample air volume large, by producing multiple ultra-violet beam illumination paths through adjacent portions of the duct for each single pulsed beam, in turn increasing the magnitude of the detected fluorescence signal.

Bio-particle fluorescence detector

A parametric generator for efficiently converting short duration pump pulses of a first frequency to a signal beam of a desired frequency is described. The parametric generator includes a second order nonlinear parametric medium, a retro-reflector, and an optical re-imaging system. Each optical sub-path through the parametric medium is substantially distinct and non-overlapping. At least two optical sub-paths have a direction within a phase matching acceptance angle of the parametric material which corresponds to the desired wavelength. The parametric generator can be configured to be compact because it utilizes multiple transmissions through the parametric medium and it employs only a single pump beam input.

Multi-pass optical parametric generator

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Lexington, MA, United States of America

Thomas H Jeys