Massachusetts Institute of Technology

Ryan Sullenberger

Yaron Rachlin

Sumanth Kaushik

Alexander Stolyarov

Thomas H Jeys

William D Herzog

Charles Wynn

Shawn Michael Redmond

Brian G Saar

David Crompton

Adam Milstein

Alexander M Stolyarov

The ability to communicate with a specific subject at a prescribed location who lacks any communications equipment opens up many intriguing possibilities. Communications across noisy rooms, hail and warn applications, and localized communications directed at only the intended recipient are a few possibilities. We disclose and show localized acoustic communications, which we call photoacoustic communications, with a listener at long standoff distances using a modulated laser transmitted toward the receiver's ear. The optically encoded information is converted into acoustic messages via the photoacoustic effect. The photoacoustic conversion of the optical information into an audible signal occurs via the absorption of the light by ambient water vapor in the near area of the receiver's ear followed by airborne acoustic transmission to the ear. The recipient requires no external communications equipment to receive audible messages.

Methods and apparatus for acoustic laser communications

Hyperspectral imaging spectrometers have applications in environmental monitoring, biomedical imaging, surveillance, biological or chemical hazard detection, agriculture, and minerology. Nevertheless, their high cost and complexity has limited the number of fielded spaceborne hyperspectral imagers. To address these challenges, the wide field-of-view (FOV) hyperspectral imaging spectrometers disclosed here use computational imaging techniques to get high performance from smaller, noisier, and less-expensive components (e.g., uncooled microbolometers). They use platform motion and spectrally coded focal-plane masks to temporally modulate the optical spectrum, enabling simultaneous measurement of multiple spectral bins. Demodulation of this coded pattern returns an optical spectrum in each pixel. As a result, these computational reconfigurable imaging spectrometers are more suitable for small space and air platforms with strict size, weight, and power constraints, as well as applications where smaller or less expensive packaging is desired.

Computational reconfigurable imaging spectrometer

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

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Somerville, MA, United States of America

Ryan Sullenberger