Douglas, this development sounds very exciting although there is obviously a fair amount of work before you can take advantage of it. I wonder whether you have any industrial sponsor for your research or is this too far for industry to notice?...Kris
For what it's worth, this effect is present at room temperature. We ran the experiment at lower temperatures for two reasons. First, reducing the temperature hinders the mobility of the Au atoms. (At room temperature, Au is surprisingly mobile, and a Au tunnel junction will show big changes in conductance as a function of time as the Au atoms at the tips move around.) Second, we wanted to work in a decent vacuum to avoid adsorbed contaminants, and cooling helps. If you make junctions like this in ambient conditions, they are rapidly coated with a monolayer of physisorbed water and pollutants, which you don't want if you're trying to understand the underlying physics.
Most optical materials are of the clear plastic variety, formed into optical fiber, but these Rice University researchers are using an angstrom-scale air-gap between gold electrodes to harness the amplification effect of plasmons, but at optical frequencies. Although such effects have been demonstrated before, this group claims to be the first to explain why the technique works as well as the first to measure how much optical signals can be amplified by angstron-scale nanogaps. When commercialized, this effect could enable sensors so sensitive that they detect a single molecule of nearly any substance. What application would you create if you had a single-molecule sensor?