Tunable photonic band schemes in two-dimensional photonic crystals composed of copper oxide high-temperature superconductors

We theoretically demonstrate the tunability of two-dimensional photonic crystals composed of copper oxide high-temperature superconductors (HTSCs). The photonic crystals we deal with are composed of rods whose axes are parallel to the c axes in the copper oxide HTSC. Photonic crystals composed of copper oxide HTSCs exhibit the large tunabilities by temperature and magnetic fields. That is, a photonic band gap increases and a midgap frequency decreases with increasing temperature and the magnetic field. Their characteristics are due to the temperature dependence of London penetration depths and the magnetic field dependence of the critical temperature and the London penetration depths. The frequency range in which the photonic band gap appears are strongly dependent on materials in the copper oxide HTSCs.