2.2-Micron, Uncooled, InGaAs Photodiodes and Balanced Photoreceivers up to 25-GHz Bandwidth

These photodiodes have applications in LiDAR sensors, telecommunications links, and pulsed laser systems.

Traditional applications for 2-micron photodetectors have been largely dominated by passive remote sensing where detectors having bandwidth of even one megahertz are deemed sufficient. The onus in such applications is to achieve low dark current through active cooling. The advent of high-power, 2-micron-wavelength lasers has made coherent LiDARs viable for active sensing applications. Such a system needs photodetectors that can handle high local oscillator optical power and have large bandwidth. Through a combination of high coherent gain and small integration time, a large signal-to-noise ratio can be achieved. Operation at high optical power levels reduces the significance of photodiodes' dark current. As a result, uncooled operation at room temperature is feasible, simplifying the overall instrument design.

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Compact, Lightweight, Athermal, Nanocomposite Telescopes with Freeform Optics

Small space missions such as CubeSats frequently require telescopes with highly sophisticated optical systems that are also low in mass and cost. The very limited spacecraft volume and mass limits also preclude adjustments to maintain critical alignment with change in temperature. Existing systems, especially those that employ folded optical paths with freeform optics, are expensive to fabricate. The optics, and support and metering structures, are also heavy due to the use of high-density material such as glass, aluminum, or nickel.

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High-Resolution, Coherent, Dual-Tip Scanning Probe Microscope

This device improves resolution, and allows for direct and accurate interpretation of topographical features without the need for a reference lattice.

The scanning tunneling microscope (STM) has become one of the most powerful tools used in studying the surface structure of electrically conducting solid-state materials at an atomic resolution. Since its conception, the STM has had the greatest impact in the field of modern surface science because of its superior capability of characterizing and resolving the surface atomic structures and defects. Surface features such as atomic point defects, dislocations, and grain boundary identification can routinely be studied using a STM. Furthermore, STMs also allow the characterization of step structures at the atomic level during the processes of surface preparation and growth of semiconductors, such as epitaxial growth on semiconductor structures.

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Fiber-Optic Environmental Radiation Dosimeter

An all-optical, fiber-optic-coupled remote radiation sensor was developed using luminescent, copper-doped quartz material. The key to the technology is the doped quartz material, which produces a luminescence signal that is directly proportional to the radiation dose.

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X-Ray Scattering Constructs 3D Images of Nanoparticle Grains

Scientists at Argonne National Laboratory have developed a new X-ray technique to see inside continuously packed nanoparticles, also known as grains, to examine deformations and dislocations that affect their properties.

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High-Resolution Imaging with Conventional Microscopes

MIT researchers have developed a method for making extremely high-resolution images of tissue samples at a fraction of the cost of other techniques, yet with similar resolution. The new technique relies on expanding tissue before imaging it with a conventional light microscope. Two years ago, the team showed that it was possible to expand tissue volumes 100-fold, resulting in an image resolution of about 60 nanometers. Now, they have shown that expanding the tissue a second time before imaging can boost the resolution to about 25 nanometers.

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Cinematography on the Fly

In recent years, a host of Hollywood blockbusters, including “The Fast and the Furious 7,” “Jurassic World,” and “The Wolf of Wall Street,” have included aerial tracking shots provided by drone helicopters outfitted with cameras. Those shots required separate operators for the drones and the cameras, and careful planning to avoid collisions. But a team of researchers from MIT's Computer Science and Artificial Intelligence Laboratory (CSAIL) and ETH Zurich hope to make drone cinematography more accessible, simple, and reliable.

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Microscope Can Scan Tumors During Surgery

When women undergo lumpectomies to remove breast cancer, doctors try to remove all the cancerous tissue while conserving as much of the healthy breast tissue as possible. But currently there's no reliable way to determine during surgery whether the excised tissue is completely cancer-free at its margins — the proof that doctors need to be confident that they have removed the entire tumor. It can take several days for pathologists using conventional methods to process and analyze the tissue.

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New Microscopy Method Breaks Color Barrier of Optical Imaging

Researchers at Columbia University have made a significant step toward breaking the so-called “color barrier” of light microscopy for biological systems, allowing for much more comprehensive, system-wide labeling and imaging of a greater number of biomolecules in living cells and tissues than is currently attainable. The advancement has the potential for many future applications, including helping to guide the development of therapies to treat and cure disease.

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Changing the Nature of Optics in One Step

Optical lenses that can see features smaller than the wavelength of light cannot be made from conventional materials. Creating “hyperlenses” that can take ultra-sharp images needs both designer materials (metamaterials) and innovative optics to be developed. Current methods for fabricating such synthetic metamaterials are complicated and involve assembling artificial cells and patterning processes. To improve the process, Texas A&M scientists developed a one-step method, which directs the self-assembly of metallic gold pillars into a special oxide using pulsed laser deposition.

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