Never say never

Sometimes it's fun to speculate about what the future will bring, and for many of us involved with "high technology" such speculation inevitably leans toward how our lives may be changed by the next great technological innovation. The conjecture can range from what may seem almost mundane predictions based on a fairly logical extension of current technology, to ideas appearing almost bizarre in their scope or impact. Although given the pervasiveness of technology in our everyday lives and the increasing rate of development, it's becoming increasingly difficult to discount any predictions as being "impossible" over the long run. So it is that the premise of one of this month's feature articles may seem rather far-fetched (see p. 113). The idea of creating an electrical power infrastructure in space based on lasers is (to put it mildly) a very long way from feasibility for many reasons, some of which are outlined in the article—but who knows what the future may bring?

Much nearer to reality, but still with a way to go, is the possibility of replacing current incandescent and fluorescent lighting with an aesthetically and economically acceptable solid-state alternative. In fact, there has been a lot of interest in the subject recently—it was the topic of a two-day technical session at last month's SPIE Annual Meeting in San Diego, CA , and is also the subject of a research initiative currently before both houses of the US Congress. Recent advances in this field involving LEDs are discussed in an article on page 81.

Elsewhere in this issue, we highlight many other technologies in various stages of development. Semiconductor optical amplifiers have been around for some time but are now gaining ground as a potential lower-cost alternative to erbium-doped fiber amplifiers in optical communications systems (see p. 73). Invented only seven years ago, quantum cascade lasers are still a relatively new type of laser and have recently moved into the far-infrared part of the spectrum opening up new possibilities for applications in trace-gas sensing (see p. 65 ). And once thought to be not user-friendly enough to be commercially viable, excimer lasers are benefiting from years of patient development and are now well-established as the laser of choice for semiconductor lithography, with new markets still evolving (see p. 103). Never say never!