EXPERIMENTAL AND THEORETICAL STUDIES OF A BROADBAND SUPERLUMINALITY IN FABRY-PEROT INTERFEROMETER

This study experimentally demonstrates a broadband (20%) superluminality in a Fabry-Pérot-like interferometer implemented on a waveguide system. A narrow wave packet propagating with an efective group velocity of 5.29 +4.28 -1.70 c without distortion was observed. The underlying mechanism is attributed to the multiple-reflection interference and the modal effect, which provide an approach for controlling the wave characteristics through manipulating the geometry of the system. Besides, the criteria of the renowned generalized Hartman effect are explicitly clarified.