Fig. 5: Multi-stepped temporal interfaces for wave amplification.
From: Experimental realization of temporal refraction and reflection in elastic beams
a The optimal distribution of the index of refraction with 4 temporal interfaces for wave amplification. b The evolution of the wave packet is simulated using COMSOL to verify wave amplification. This wave packet, with a central frequency of 6 kHz, consists of 5 cycles for tf = 6 ms and spans a length of L = 2.56 m. c Refraction and reflection coefficients as a function of the normalized incident frequency f/f0, 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 of data at t/tf = 0.75 in (b).
