Patrolling national borders, detecting explosives and weapons in luggage and cargo and scanning battlefields for toxins are different tasks, yet they all have something in common. They are undertaken to ensure global security, the need for which is at an all-time high. At the heart of the performance of these tasks lie integrated photonics, optics and electro-optics, a combination that’s helping to build a safer world.While some of the technologies used in these applications are new, others are improvements to existing technologies. Increasing sensitivity is one goal in the improvement of optically based biosensors.Increased power and miniaturization also are important; for example, with tunable, compact IR lasers used in detection areas. In the thermal imaging realm, photonic capabilities coupled with MEMS technologies are enabling the development of hyperspectral and broadband imaging. According to Lt. Col. John C. Carrano of the Defense Advanced Research Projects Agency’s Microsystems Technology Office, this will enable hyperspectral imaging on a single chip on a single focal plane array. Large, computationally intense hyperspectral imaging systems have been used in the past — e.g., on the battlefield to detect tanks under camouflage nets. Put in a smaller package, hyperspectral imaging could give us “certain wave bins in the spectral domain,” Carrano said, and would be useful in exploring the spectral content of the item of interest.Reducing response time also is a goal. With the combination of electro-optic devices and increased miniaturization, sophisticated fluorescence systems are being packaged for portability. Anthrax detection or discovery of airborne toxins may soon give on-the-spot feedback.Communications is another area that is being enhanced through the combination of new technologies. Free-space communications is an important area under development. In the past, large gimbaled mirrors were needed to steer a laser beam. Now, optical phased arrays will enable photonic or electronic beam steering, removing the need for the large mirrors. Carrano expects that battlefield and other emergency communications may be done someday with a small handheld gadget that will communicate at gigabit-per-second bandwidths.The following group of articles looks at a variety of photonics technologies at work in real-world applications. From testing the neighborhood water supply to a new 3-D technology that could help guide missiles, photonics is proving to be a dominant technology for understanding and safeguarding our world.