Science has been advancing at quite a rate in more recent times and this is only one of the amazing things to come. Scientists have recently proposed a theoretical way that light could be slowed down to a literal complete stop.
This research was published in Physical Review Letters and goes over something known as ‘exceptional points.’ The authors of this study go over in this study how methods used before were able to slow light speeds down almost to zero but just did not make the cut. This new method is completely different. While the old methods included using a cloud of ultracold atoms of sodium to slow light down the new method uses a waveguide.
A waveguide, for those who do not know, is a structure that works to guide the waves like a tube to create exceptional points. These are areas where two complex wavelength patterns are able to meet and merge as one. Light is a wave most of the time and waves are constantly moving and changing their shape.
For a very long time, scientists thought exceptional points were merely theoretical concepts altogether but in 2010 that all changed. That was the year that researchers were able to build one in the real world by firing microwaves through a metal box built specifically for that purpose. While we have not yet stopped light in real time, it does seem very do-able.
“Almost twenty years ago, light was slowed down to less than 10 – 7 of its vacuum speed in a cloud of ultracold atoms of sodium. Upon a sudden turn-off of the coupling laser, a slow light pulse can be imprinted on cold atoms such that it can be read out and converted into a photon again. In this process, the light is stopped by absorbing it and storing its shape within the atomic ensemble. Alternatively, the light can be stopped at the band edge in photonic crystal waveguides, where the group speed vanishes. Here, we extend the phenomenon of stopped light to the new field of parity-time (PT) symmetric systems. We show that zero group speed in PT-symmetric optical waveguides can be achieved if the system is prepared at an exceptional point, where two optical modes coalesce. This effect can be tuned for optical pulses in a wide range of frequencies and bandwidths, as we demonstrate in a system of coupled waveguides with gain and loss.”
Sure, stopping light might be theoretical right now, but this theory in itself is going to open up a lot of doors. If this proves to work in time we will be headed somewhere completely unexpected. This could bring about some very interesting advances for slow light applications and other useful things. What do you think about all of this? I for one am curious to see how it plays out.