For over 50 years, scientists theorized that an electromagnetic wave could be reflected temporally – not just spatially.
According to, scientists could not confirm the existence of reflection in time, due to the amount of energy needed to create a interface temporal.
Through a Projected MetamaterialNew York scientists got successfully observe temporal reflections for the first time.
The explanation of spatial reflections – either by light or by sound – It’s quite intuitive. Electromagnetic radiation in the form of light or sound waves reaches a mirror or wall, respectively, and changes direction, which allows the Our eyes see a reflection on quantum mechanicsknown as temporal reflection.
Temporal reflections require a uniform variation throughout the electromagnetic fieldscientists assumed that it would be necessary too much energy to observe the temporal reflections in action.
But researchers at the Cuny Graduate Center (Cuny Asrc) advanced scientific research center in New York have successfully observed temporal reflections by sending broadband signals for a metal strip full of electronic interruptions that were linked to reservoir condensers.
In this way, the researchers were able to trigger the introductors at ease, doubling impedance along the strip. This sudden change It caused the signs to transport a successful inverted copy in time. The results were in the magazine Nature Physics.
“It is very difficult to change the properties of a medium in a fast enough, uniform and with enough contrast to reflect the electromagnetic signals in time, since they oscillate very quickly,” he said Gengyu Xuco-author and postdoctoral student at Cuny ASRC.
“Our idea was to avoid altering the properties of host material and, instead, creating a metamaterial in which additional elements can be abruptly added or subtracted through quick interruptions“.
This temporal reflection also behaves differently from spatial reflectionssince this time echo reflects first the last part of the signal.
Investigators say that if we look at a temporal mirrorWe would see our backs instead of our face. To acoustically translate the experience, it would be like listening to a rewinding cassettethat is, fast and acute.
The change of frequency, if it could be perceived by our eyes, would be similar to colors of light that suddenly change to another colorlike red to change to green.
This strange counter-introductive nature of time reflection It is part of what has made the study of the concept so difficult.
“It has been very exciting to see thisbecause this counter-introductive phenomenon has long been predicted and because the waves reflected in time behave differently from the waves reflected in space, ”he said Andrea Alùcorresponding author and teacher of physics and director of the photonical initiative of CUNY ASRC.
The big question is “why scientists worked to Recreate this theoretical reflection of time in a laboratory? A more thorough control of electromagnetic waves can greatly improve wireless communications And even lead to Advances on low energy computers Based on waves.
In other words, it is simply useful to know everything about electromagnetic waves, both front and backwards.
Teresa Oliveira Campos, Zap //
