Photonic band gaps of a two-dimensional square lattice composed by superconducting hollow rods

• The photonic band structures for hollow superconducting cylinders were calculated.
• New photonic band gaps were finded in comparison with solid superconducting rods.
• The quantity of photonic band gaps can be modulated by means of the width of shell.
• The photonic band gaps can be shifted by means of the system temperature.
• The ratio gap–midgap show the behavior of band gaps with the increasing of the inner radius.

In this paper by means of the plane wave expansion method, we have calculated the photonic band structure of 2D photonic crystals consisting of high temperature superconducting hollow cylinders arranged in a square lattice. Band structures were obtained at low frequencies and assuming TM polarization of the incident wave, for different inner radii of the cylinders and for two different temperatures (5 K and 15 K), showing the tunability of photonic band gaps with respect to these parameters. Interesting features, such as the decreasing of cutoff frequency and separation of photonic modes were observed by increasing both the temperature and inner radius. Permittivity contrast and the difference between the inner and outer radius lead to the appearance of new band gaps when compared with the case of solid cylinders. These band gaps can be modulated by the width of the shell and temperature, which may be used for the development of novel optical devices.