Josephson plasmonics in layered superconductors

We review the optical physics of Josephson plasmons in cuprate superconductors. These coherent charge modes arise from tunneling of the superfluid between superconducting planes and exhibit strong nonlinearities and quantum coherent dynamics at THz frequencies. We summarize early transport and microwave experiments in Bi2Sr2CaCu2O8+δ (BSCCO) and discuss more recent work performed in La2−xSrxCuO4 (LSCO) and La2−xBaxCuO4 (LBCO) using nonlinear THz techniques. We cover THz-driven oscillations between superconducting and resistive states, optical excitation of solitonic breathers, and the parametric amplification of Josephson plasma waves. The last part of the review discusses some new research directions, including cooling of superconducting phase fluctuations with lasers and optical cavity control techniques