Novel Sensing and Detection

The intensity of light that propagates through glass optical fiber is fundamentally limited by the glass itself. A novel fiber design using a hollow, air-filled core removes this limitation and dramatically improves performance by forcing light to travel through channels of air, instead of the glass around it. DARPA’s unique spider-web-like, hollow-core fiber, design is the first to demonstrate single-spatial-mode, low-loss and polarization control—key properties needed for advanced military applications such as high-precision fiber optic gyroscopes for inertial navigation.

Microelectromechanical systems, known as MEMS, are ubiquitous in modern military systems such as gyroscopes for navigation, tiny microphones for lightweight radios, and medical biosensors for assessing the wounded. Such applications benefit from the portability, low power, and low cost of MEMS devices. Although the use of MEMS sensors is now commonplace, they still operate many orders of magnitude below their theoretical performance limits. This is due to two obstacles: thermal fluctuations and random quantum fluctuations, a barrier known as the standard quantum limit.

As satellites become more common, they face growing risk of colliding with space debris and even each other. The U.S. Department of Defense has thus made space situational awareness a top priority to maintain communication, Earth observation and other critical capabilities upon which military, civilian and commercial functions rely. Traditional telescope technology, however, has difficulty finding and tracking small objects—such as debris and satellites—across wide tracks of sky, especially at the increasingly crowded geosynchronous orbits roughly 22,000 miles above the Earth’s surface.

Raman spectroscopy uses lasers to measure molecular vibrations to quickly and accurately identify unknown substances. Ultraviolet (UV) lasers have the optimal wavelength for Raman spectroscopy at stand-off distances, but the Defense Department’s (DoD) current UV-based tactical detection systems are large and expensive and have limited functionality. A new DARPA program seeks technology that may make UV-based detection equipment more readily available in the field.

Cost and complexity limit the number of ships and weapon systems the Navy can support in forward operating areas. A natural response is to offset these costs and risks with unmanned and distributed systems. But how do such systems get there in the first place?