Although based on a numerical simulation, the images depicting "liquid light" droplets on this month's cover serve to underscore some of the intriguing research taking place at the frontiers of photonics (see p. 17). While the idea of light as a fluid may seem far fetched, it's worth remembering that many of the phenomena we now take for granted were once just as thought provoking as the idea of liquid light. And harnessing such unlikely phenomena has ultimately led to many of the optoelectronics technology applications we cover regularly in Laser Focus World.
Skeptics initially doubted the concept of photonic-crystal optical fiber, for example, but in 1995 Philip Russell and colleagues at the University of Bath (England) fabricated holey fiber, opening up a range of new fiberoptic applications based on transmission properties that could be adjusted (see p. 77). More recently, the emergence of molecular-scale engineering or nanotechnology has the potential to create a host of new materials with novel properties. Commercial applications are, for the most part, still in the future. But a cold cathode x-ray tube based on carbon nanotubes may represent a significant step towards miniature portable x-ray sources (see p. 22). And in another example, nanomaterials could help improve flat-panel color displays—electric-field directed layer-by-layer assembly of nanocrystals allows preselection of emission color by particle size in electroluminescent displays (see p. 44).
With cautious optimism
Cool research notwithstanding, the economic state of current optoelectronics applications is a significant issue for our readers so I was encouraged recently by the cautious but mostly upbeat mood at Semicon West in July. The mood on the floor was bolstered by that industry's June book-to-bill ratio of 1.28 (meaning that $128 worth of new orders were received for every $100 of product billed for the month), which continues seven months of sequential order growth. Because materials processing (including semiconductors) is currently the leading market for lasers, any recovery within that sector ought to bode well for a healthy cross section of photonics firms. And not only is the business outlook somewhat better . . . at least two novel laser applications were reported at Semicon. One involves laser tools for the micromachining of silicon; the other, a new laser annealing capability targeted at sub-100-nm feature sizes (see p. 32).