Enhancement effect of cumulative second-harmonic generation by closed propagation feature of circumferential guided waves
Gao Guang-Jian1, Deng Ming-Xi2, †, Hu Ning2, Xiang Yan-Xun3, ‡
       

Temporal signals received at points P and Q in Fig. 1; (a) only S1 is driven by D1(r, t), and (b) both S1 and S2 are simultaneously driven by D1(r, t) and D2(r, t).