Fig. 4: Multi-stepped temporal interfaces for anti-reflection.
From: Experimental realization of temporal refraction and reflection in elastic beams
a Schematic diagram illustrating a wave propagating through multi-stepped temporal interfaces. The setup consists of two temporally semi-infinite media with a cascade of M temporal slabs, separated by M + 1 temporal interfaces. b, e The optimal time-dependent index of refraction function designed for anti-reflection of a single frequency (b) and broadband frequency (e). c, f Wave packet evolution by COMSOL simulation for verifying anti-reflection of a single frequency (c) and broadband frequency (f). The wave packet, with a central frequency of 6 kHz, consists of 5 cycles in time, with tf = 6 ms and L = 2.56 m. d, g Refraction and reflection coefficients as a function of the normalized incident frequency f/f0 for single frequency (d) and broadband frequency (g) anti-elimination, where f0 = 6 kHz, with circles representing numerical simulation results and solid lines representing analytical calculations using the transfer matrix method. The subscripts “s” and “a” denote simulated and analytical results, respectively. The results are obtained from the Fourier transform at t/tf = 0.75 in (c) and (f).
