New technology challenges the old

Since their invention nearly 40 years ago, lasers have opened up many completely new fields-optical data storage, for example, and laser-based leveling in construction and agriculture. Some technical enterprises, though, were around long before lasers arrived. The concept of movable type for printing-in Europe at least-dates back to the 1400s and is generally credited to Johannes Gutenberg, a German who devised a way to use metalworking techniques-such as casting, punch-cutting, and stamping-for the mass production of books. The potential of lasers to advance commercial printing (or reprographics) technology was recognized early on, but the first devices raised as many questions as they answered. In fact they started what must be one of the largest-ever ongoing technology upheavals in a single field, with multiple technologies-related but different-all struggling for ascendancy. Among other developments, such as new media and smaller, more cost-effective lasers, the advent of cheaper and more-powerful computers solved many problems so that the all-digital press is now a reality. Today, commercial printing encompasses technologies ranging from the "conventional" offset printing press to fully digital computer-to-plate presses. But the technology war is far from over, and the newest lasers are offering still more choices to commercial printers (see p. 79).

Laser developments are driving changes in other fields, too. In materials processing applications, high-power systems provide kilowatt-level output-enough to cut metal-while micromachining systems provide micron-level precision at milliwatt-range output power. The most recent slab-type carbon dioxide lasers are allowing more power to be obtained from smaller packages, offering increased flexibility in industrial applications (p. 129). And at the other end of the size scale, laser-based devices are increasingly becoming the tools of choice for machining microparts, according to contributing editor Eric Lerner (p. 87).

Beyond lasers

Not all optoelectronics applications involve lasers, however. A relatively new type of grating-the volume-phase holographic grating-can achieve higher diffraction efficiencies than classical surface-relief gratings and could result in improvements to the performance of certain next-generation astronomical spectrographs (p. 93). Meanwhile, performance enhancements to intensified charge-coupled devices (CCDs) have benefited both spectroscopic and imaging applications. This month's cover story (p. 69) highlights studies using an intensified CCD camera with laser-induced incandescence to monitor combustion.