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Scientists "Freeze" Light!

Jawid Hassim
Prof. Thomas Halfmann

Something that many probably never thought was possible and perhaps goes against a few perceptions people may have had over the course of their lives or might have even been taught by educators and religious institutions. "Let there be light!" so important to our anthropological development that we have made it a synonym for knowledge, wisdom, insight and awareness (i.e. enlightenment and illumination)

Those of us in the electronics and information world are of course no strangers to the concept of manipulating light for various purposes. Fibre optics through which data is transmitted is an example of this; I find it kind of funny how that ancient parallel between transmission of information and light takes on a more tangible construct through our technological advancements. Aside from this we have many other everyday components (barring the light-bulb) used in electronics that have a strong correlation with light; phototransistors, solar panels, LDRs etc. More interesting stuff like semiconductors that make use of slow light have been around since mid-2000.

Photonics is a branch science dedicated to understanding of light. Researchers from the Technische Universität Darmstadt (which if you haven't guessed already is in Germany) managed to suspend light for a full-minute (60 seconds, longest so far)

So at this point you’re likely wondering how exactly this brave new feat was achieved. Basically: Through a technique known as Electromagnetically Induced Transparency (EIT) which is more or less interference in the spectral range of the light causing the opaque region to (visibly) 'disappear', in this case the light from a laser aimed at crystal which changes the latter's refractive index. Then a second laser is fired at the precise moment at which this quantum reaction occurs (between the first beam of photons and the crystal)

Once the second beam is stopped the reaction is complete and light is trapped inside of the crystal. These "frozen" photons are converted into spin-waves which remain stored inside crystal until the secondary laser is fired again, reversing them back into light which then (One can say) leaks back out of the crystal.

What does this latest stride mean for us ordinary folks? I would wager that in the not too distant future, we may be looking forward to new forms of data storage which people will inevitably call by some cool conjunction like 'photodisk' or something like that. Until then - it's still pretty "cool".