New Molecules for a Faster Internet

Roland Piquepaille writes "An international team of researchers has discovered a new generation of optical molecules which interact 50% more strongly with light than any molecules ever tested. These organic molecules, known as chromophores, have been theorized by physicists at Washington State University, synthesized by chemists in China and tested for their actual optical properties by chemists in Belgium. But if they're excellent candidates for being used in optical technologies such as optical switches and Internet connections, these new materials should not be used before several years — if ever. Read more for additional details and a picture of the physicist who broke a law he established in 1999."

Comments

Re:Similarly confused...

[kebes]

The summary and Roland's article (not surprisingly?) get the details about these 'limits' somewhat wrong. If you read the intro to the arXiv article (warning: PDF), they say:

Quantum cal-culations using sum rules have been used to place an upper-bound on the molecular susceptibilities; [1, 2, 3, 4] but, the largest nonlinear susceptibilities of the best molecules fall short of the fundamental limit by a factor of 10^(3/2).[4, 5] A thorough analysis shows that there is no reason why the molecular hyperpolarizability can not exceed this apparent limit.[6] In this letter, we report on a novel set of molecules where the one with modulated conjugation[7] is found to have a hyperpolarizability that breaches the apparent limit.

If you look up reference [4], which you can find here, you see this is an "Erratum" (publication pointing out a mistake you made in a previous publication). In it, he shows (see graph), that what he previously plotted as the "limit" was a plotting mistake (not a theoretical mistake). So what he claims is that there is a fundamental (quantum) limit, but there is also an "apparent limit" based on the accumulated experimental data on chromophores so far.

Thus, this new paper is claiming to have broken through an "apparent limit" that existed before. Nothing fundamental about this limit, of course... it was merely that synthetic chemists had yet to be able to create molecules that good. This new report is a 'breakthrough' in the sense that they've made molecules with still higher nonlinear susceptibilities. (But still not violating the theories...)

Will this ever show up in real technology? Probably not. In 'real devices' of course having good optical response is only half the challenge. It must also be cheap enough, stable enough, easy to process, etc. So it's a step forward, but I would call it's more a 'pushing the edge of what can be synthesized' rather than a 'telecom breakthrough' as Roland tries to spin it.