Time dilation and time reversal with the multiple-wavelengths range-gated active imaging principle

Abstract

The possibility of realizing time dilation and time reversal of events taking place in a scene by using the multiple-wavelengths range-gated active imaging (WRAI) principle in superimposed style was studied. Both temporal behaviors could be analyzed as a function of time since the WRAI principle allows different positions of the object in the image to be frozen at different moments according to the wavelengths. As the speed of the photons varies in the function of the refraction law of the crossed medium, different media were used to intervene in the time of the events recorded by the camera. Different wavelengths were used to select these media. By increasing the refractive index of the crossed medium as a function of time, the scene events arrived chronologically with an increasing delay compared to the events seen in the open, giving the impression of slowing down time. Similarly, by decreasing the refractive index of the crossed medium as a function of time, the scene events arrived chronologically in the opposite direction compared to the events seen in the open, giving the impression of going back in time. Experimental test results validated the theoretical part and the possibility of observing these different temporal behaviors with the multiple-wavelengths range-gated active imaging principle in superimposed style.