Air Force Research Lab and Industry Advance Multi-Junction Solar Cells

Experts at the Air Force Research Laboratory (AFRL) continue to expand the scope of their technological expertise, rising above the Earth’s surface to meet the power needs of next-generation military spacecraft. A collaborative effort between the AFRL Materials and Manufacturing and Space Vehicles directorates, the Space Industrial Base Working Group, and SolAero Technologies has resulted in state-of-the art, multi-junction solar cells destined to reduce costs and increase power efficiency for military space applications.

Posted in: News, Defense, Solar Power, Materials, Photonics

Army Developing Lasers That Pierce Fog, Dust to Destroy Targets

A lot of people think that high-energy lasers, or HELs, can't penetrate fog, rain and dust, said Thomas Webber, director of the Directed Energy Division's Technical Center, U.S. Army Space and Missile Defense Command. That's just plain wrong.

Posted in: News, Defense, Lasers & Laser Systems, Optics

Identifying and Isolating Signals Using Radio Frequency Photonics

A single antenna can be used for both transmission and reception. To accomplish this, the transmission must be isolated from the reception. In Figure 1, a radio frequency (RF) circulator is connected right after the antenna. The three-port device separates the transmit path from the receive path. After the circulator, a system can be used to identify the frequency of different signals. Once the frequency has been found, a filter with the right pass-band frequency can be used to isolate signals from each other.

Posted in: Articles, Aerospace, Communications, Wireless, Fiber Optics, Lasers & Laser Systems, Optical Components, Optics, Photonics, Antennas, Radio equipment

Researchers Show How Fear Memories Can Be Erased

Researchers at the University of California, Riverside have devised a method to selectively erase particular fear memories by weakening the connections between the nerve cells (neurons) involved in forming these memories. A sight, sound, or smell we have sensed may not later trigger fear, but if the stimulus is associated with a traumatic event, such as a car accident, then fear memory is formed, and fearful responses are triggered by the stimulus.

Posted in: News, Defense, Medical, Photonics

Robot’s Speed-of-Light Communication Could Protect You From Danger

Cornell University researchers are developing a system to enable teams of robots to share information as they move around, and if necessary, interpret what they see. This would allow the robots to conduct surveillance as a single entity with many eyes. Beyond surveillance, the new technology could enable teams of robots to relieve humans of dangerous jobs such as disposing of landmines, cleaning up after a nuclear meltdown or surveying the damage after a flood or hurricane. The project, called “Convolutional-Features Analysis and Control for Mobile Visual Scene Perception,” is supported by a four-year, $1.7 million grant from the U.S. Office of Naval Research.

Posted in: News, Defense, Machine Vision, Visualization Software, Optics, Robotics

Heads-up Display Improves Soldiers’ Situational Awareness

A novel technology called "Tactical Augmented Reality," or TAR, is now helping soldiers precisely locate their positions, as well as the locations of friends and foes. It even enables them to see in the dark, all with a heads-up display device that looks like night-vision goggles (NVG). In essence, TAR replaces NVG, GPS, plus it does much more.

Posted in: News, Defense, Optical Components, Optics

Laser Integration on Silicon Photonic Circuits Through Transfer Printing

The purpose of this project was to develop a transfer printing process for the massively parallel integration of III-V lasers on silicon photonic integrated circuits. Silicon has long offered promise as the ultimate platform for realizing compact photonic integrated circuits (PICs). That promise stems in part from the material's properties: the high refractive-index contrast of silicon allows strong confinement of the optical field, increasing light-matter interaction in a compact space—a particularly important attribute for realizing efficient modulators and high-speed detectors.

Posted in: Briefs, Aerospace, Photonics, Integrated circuits, Lasers, Fabrication, Materials properties, Semiconductors

High Energy Computed Tomographic Inspection of Munitions

An advance computed tomography (CT) system was recently built for the U.S. Army Armament Research, Development and Engineering Center, Picatinny Arsenal, NJ, for the inspection of munitions. The system is a charged coupled device (CCD) camera based CT system designated with the name “experimental Imaging Media” (XIM). The design incorporated shielding for use up to 4MeV x-ray photons and integrated two separate cameras into one single field of view (FOV). Other major distinguishing characteristics include its processing functions to digitally piece the two cameras together, use of advanced artifact reduction principles, performing reconstruction simultaneously during acquisition, and its development in accurate beam hardening corrections through digital means.

Posted in: Briefs, Aerospace, Photonics, Charge coupled devices, Imaging, Defense industry, Inspections, Missiles

Development of Photoacoustic Sensing Platforms

In recent years, photoacoustic spectroscopy (PAS) has emerged as an attractive and powerful technique well suited for sensing applications. The development of high-power radiation sources and more sophisticated electronics, including sensitive microphones and digital lock-in amplifiers, have allowed for significant advances in PAS. Furthermore, photoacoustic (PA) detection of IR absorption spectra using modern tunable lasers offers several advantages, including simultaneous detection and discrimination of numerous molecules of interest. Successful applications of PAS in gases and condensed matter have made this a notable technique and it is now studied and employed by scientists and engineers in a variety of disciplines.

Posted in: Briefs, Aerospace, Photonics, Amplifiers, Electronic equipment, Lasers, Sensors and actuators, Spectroscopy, Acoustics

Fiber Optic Rotary Joints Add a Spin to Sensing, Mobile, and Robotic Fiber Systems

To the passing optical signals, fiberoptic rotary joints (FORJs) are nothing more than fiber connectors, which provide connection between one or multiple fibers. Their unrestricted ability to rotate, however, gives them a critical role in many sensing, mobile, and robotic fiber systems such as ROVs (remotely operated vehicles), aerostat radars, submarines, satellite antennae, OCT (optical coherence tomography), mining vehicles, cranes, wind turbines, robotic vehicles, broadcasting (mobile cameras), etc. This article discusses some of the applications where optical rotary joints are indispensable.

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Posted in: White Papers, White Papers, Photonics