Fiber sensors catch high-tech glitches

Our society's growing reliance on a highly integrated set of interlocking technologies is not news, but it does create an intriguing paradox. As these technologies push efficiencies to new levels, often by eliminating any slack in a system, it becomes much easier for a small glitch to bring that system to its knees as the effects of the problem ripple through the system and leave multiple problems in its wake. A fault that disables a single commercial airliner, for example, can have far-reaching effects as multiple subsequent flights get canceled because the aircraft and its crew are not where they should be.

Finding ways to address such problems is becoming a critical aspect of our high-tech society, and real-time routine testing of civil infrastructure

Other optically based methods of sensing can involve the detection of light, either in rather specialized situations such as monitoring the output of a clinical diagnostic instrument with a photomultiplier tube (PMT) or, more generally, for imaging, such as with charge-coupled-device (CCD) arrays. Both devices are featured this month: PMTs are particularly useful in low-light situations (see p. 99), while the current state of CCD technology

Lasers process even more materials * Research into the effects of laser light on specific materials is ongoing, and its results benefit various aspects of materials processing. This month we highlight both old and new applications. Laser marking, for example, is well established, but new marker capabilities?such as multicolor marking?are emerging (see p. 123). In the semiconductor industry, where laser light already is used extensively as a production tool, a new application with potential is laser annealing of semiconductor material (see p. 105). Another expanding application is laser cutting. Although other technologies exist, lasers were chosen for precision cutting of imaging slits in spectrographic masks (see p. 111).

Stephen G. Anderson
Executive Editor