We’ve all had this moment: one instant we’re too tired or distracted to think about the words coming out of our mouths and the next thing we know, we’ve said something that, to put it lightly, doesn’t exactly reflect that brilliant, intellectually stimulating side of ourselves. Ever wish you could change history to erase that one very minimal, but very irritating thing that happened to you recently? Well, as of last year, physicists are exploring the possibility for us to do so.
Researchers at Cornell University have been manipulating optics and light energy to create a temporal cloak, a system that acts as a “history editor” by erasing data about light waves that have passed through the clock. Placing an optical fiber between two “time lenses” and then passing light waves through that fiber allows this to be done. At the exact instant at which the light would pass through the area between the two glass lenses, it appears as if there is a gap in the light’s travel path. This gap creates a concealment effect in which, for a tiny fraction of a second, it appears that the light waves had never been there.
Simple, right? Not exactly. The temporal cloak strongly relies on placing very stringent restrictions on the light waves’ ability to travel and on their properties. In order to be able to veil the light waves, the area in which they are allowed to travel must be reduced to its most minimal size. For this to occur, the velocity of light waves has to simultaneously accelerate and decelerate. Thus, as the light waves are traveling down the linear path of the optic fiber, they accelerate when they approach the center of the time lens and slow down when touching the lens’ circular edges. The light is then drawn out to the very edges of the area between the lens, creating an effect in which the majority of the area appears hollow. The light ways are pushed back into their former linear path and velocity with the use of a second lens at the other side of the system.
Light frequency was used to measure the effectiveness of the temporal cloaks’ empty zone. When the light waves were not forced to accelerate at its center, pulses traveled through the region at a rate of 41 kilohertz. Turning on the system eliminated any pulse detection that was occurring. All evidence that light had been passing through that region just moments ago was eliminated.
As of now, it is only possible to manipulate “history” in terms of short waves of light, but if our eyes and our measuring equipment can be deceived into believing that these events have never occurred, there is no telling what future innovations in this field may bring. Looking ahead into the future, maybe one day that sudden surge of regret that you feel after saying something you shouldn’t have said will not be a long-lasting problem at all.
But for now…watch yourself.