Computer simulation on terahertz emission from intrinsic Josephson junctions of high- Tc superconductors

Solving coupled nonlinear sine-Gordon equations and Maxwell equations numerically, we study the electromagnetic and superconducting properties of the single crystal of high- Tc superconductor Bi2 Sr2 Ca Cu2 O8+δ with a static magnetic field applied parallel to the ab plane and a dc fed in along the c axis. Cavity resonances of transverse plasma occur in the intrinsic Josephson junctions with frequencies in terahertz regime. It is revealed that the electromagnetic wave can transmit from the junctions into space. The emitted energy counted by the Poynting vector is about 400 W cm2. The frequency as well as the energy of emission can be tuned almost continuously by the current and magnetic field.