Shortly after the invention of the laser many predictions were made about this new coherent light source and its possible capabilities. Aside from the well-worn joke about a "solution looking for a problem," serious attempts to apply laser and optoelectronics technologies have ranged from energy-beam weapons to medical therapy and have met with varying degrees of success. One of the largest commercial applications is optical data storage, which, in the guise of the compact disc, was responsible for putting a laser in almost every home. But another form of optical storage, based on holography, has been around almost as long, and, although it seems to promise random access to very-high-density data, it has yet to emerge from the laboratory (see cover and p. 123). Yet another form of optical data storage, that of holographic imagery, also has been around for several decades with little commercial success, but that may be changing as high-resolution three-dimensional (3-D) display images gradually emerge from specialist studios into the real world (see p. 117). Elsewhere, recent developments in 3-D imaging on a microscopic scale have benefited research into the movement of biological microorganisms and into current flow in semiconductors among other areas (see p. 141). And real-time imaging at infrared wavelengths has penetrated such "old world" industries as steel production (see p. 135).
Precision measurement was one of the earliest uses of lasers and detectors and it is still a major application today. Adding a beam scanner and computer allows full-size sculptures to be reproduced almost automatically from small models after the models have been scanned by a laser (see p. 167). So, while some of the most anticipated applications—such as energy-beam weapons—have yet to materialize, there is now an abundance of "real world" optoelectronics applications in all aspects of our lives, with many more to come (see p. S5).