Stand-alone speedometer directly measuring the translational speed based on the difference between dispersive dragging effects of different media

摘要

A stand-alone speedometer includes an electromagnetic wave source, a beam splitter, a detector and two media with different dispersive dragging effects. An electromagnetic wave is divided into two beams by the beam splitter. The two beams pass the two media differently and they combine again to go on to a detector, giving rise to interference which records the travel-time difference between two beams. Because the two media have different dispersive dragging effects on the propagation of the electromagnetic wave, measuring the change of the travel-time difference when the apparatus is stationary to that when the apparatus is moving will give the translational speed of the apparatus.