In the tossing game of horseshoes, a "ringer" is the reassuring "clank" of an iron horseshoe making a direct hit on the goal post; it scores two points. From the opposite end of the pit, an experienced player knows without seeing that the shoe is secure against the post and success could be near. Then, when the opponent tosses and the same sound is heard, the competition heats up!
Basic scientific research is sometimes like a game of horseshoes, with similar back and forth competition. A problem presents itself, and several researchers tackle it. Because of the way most funding is awarded, not many researchers are given grants for identical projects, so the horseshoe race is on. (Projects of great importance, however, may be amply funded—for example, the race for blue-green-emitting diode lasers and the cure for AIDS.)
The competition continues as research teams take turns making incremental advances. Once the technique is refined, applications become important. The technique of cavity ringdown laser absorption spectroscopy described on p. 71 (and shown on the cover) has been tossed back and forth for more than 10 years. As the authors explain, this measuring technique, while seeming complex, really isn't—through the decrease in light "ringing" in a cavity, parts-per-million concentrations can be measured directly. Applications include gas-phase molecular complexes and combustion studies.
Pfft! Ultraviolet lasers vaporize materials
Lasers can cause damage through their focused high intensity in the ablation process—material is essentially vaporized. To prevent eye damage, there's a well-known (and unfortunately often ignored) mantra: "Wear your safety glasses" (see p. 127). A growing application of UV lasers is in ophthalmology, in which laser pulses reshape the cornea of the eye to correct vision. This year, the American Chemical Society recognizes former IBM researcher R. Srinivasan with its "Award in Creative Chemistry" for his pioneering work studying photoablation with UV light. Besides corneas, a host of polymeric materials can be ablated. This property can be exploited to create tiny specialized patterns in a variety of materials (see p. 83). Imagination seems to be the key to this rapidly expanding area of micromachining and fabrication.
We hope these experiments continue to be met with the ringing of applause and the resounding clank of success.
