“What a mess!”. An expression that we use every day, not always by the way, to indicate a situation that is beyond our control and of which we cannot predict the outcomes, which are almost always undesirable. Yet, even in chaos there is good. And the optical scientists have been studying for some time, in an attempt to exploit it, in some way guide it, for our purposes. But they had never quite captured, filmed and photographed him yet. Thanks to one of the fastest cameras in the world, the feat was succeeded by a team of researchers from the California Institute of Technology and of University of Southern Californito. They used a technique known as “Compressed Ultrafast Photography” (CUP) by recording video at one billion frames per second. But the CUP allows more, much more, reaching performance in the trillions of frames per second. Monstrous speeds that allowed the researchers to capture and study the path of the laser light as it chaotically “bounces” in specially designed cavities for this to happen.
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The applications and perspectives of this research are innumerable. Chaotic behavior, in fact, is a practically omnipresent phenomenon in nature. The full understanding of its mechanisms will increasingly influence fundamental research areas such as Biology, Physics and Mathematics, as well as the future of applications and technologies such as robotics and optical cryptography. The latter has been thoroughly studied – and for some time – also in Italy. It is the case of Valerio Annovazzi Lodi – Full Professor at the Department of Industrial and Information Engineering of the University of Pavia – who has given an important hand to the progress in the study of optical chaos and its applications. Cited, not surprisingly, among the research references by his Californian colleagues, Annovazzi and his group have long studied chaotic optical encryption.
“The basic idea – explains the professor – is to hide a message in the chaos so that only an authorized user can recover it”. This message, in itself, is not intelligible. The authorized recipient, however, “can erase the chaos and recover the message by generating identical chaos and subtracting it, thereby erasing the chaos superimposed on the message.” The safety of this technique – Annovazzi specifies – “lies in the fact that to generate the same chaos at the receiver it is necessary to use a laser almost identical to the one that generated the chaos at the transmitter”. And, for a potential attacker, “having two identical lasers, or nearly so, is very difficult if they are not selected a priori in the production phase”. A practically impenetrable system that would require specific hardware and for professionals: “Being a technique on a physical level – the professor observes – it is certainly not enough to guess or copy a password!”.
Future developments? Annovazzi sees many. For example, in the field of security in optical transmission in open space (rather than in fiber, therefore with greater communication privacy problems) which plays an important role in countries such as China and India, where the very rapid evolution of optical networks does not always allow the immediate wiring of new neighborhoods and buildings. One of the many examples, the one just seen, capable of making us see chaos as an opportunity, an ally – uncomfortable at times, but indispensable – for many of our purposes. Somehow giving reason to Nietzsche: “You have to have chaos within yourself to give birth to a dancing star”.
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