外磁场与温度对低温超导光子晶体低频禁带特性的影响

文中用传输矩阵法(TMM)分析了TM波垂直入时,超导光子晶体的低频禁带特性,并讨论了外磁场与温度对禁带的影响.分析结果表明:超导光子晶体存在频率从0开始的低频禁带;当没有外磁场作用时,由于超导中正常态电子的影响,低频禁带的截止频率与温度无关;有外磁场作用时,温度才对截止频率具有可调性.外加恒定磁场时,低频禁带的截止频率随温度升高而减小;而在正常态电子的作用下,温度对处在超导态超导光子晶体禁带截止频率的调节范围相对忽略正常态电子情况下减小.恒温下,通过调节外磁场来控制带隙时,正常态电子的贡献很小可忽略不计;外磁场强度增大禁带截止频率减小.当超导体完全处于正常态时,低频禁带消失.

Effects of external magnetic field and temperature on low frequency photonic band width in cryogenic superconducting photonic crystals

Superconducting photonic crystals are artificial periodic structures composed of superconductors and dielectric structures. In this paper, the transfer matrix method(TMM) is used to study the transmittance of one-dimensional photonic crystals consisting of cryogenic superconductor and lossless dielectric for TM wave. It is shown that a stop band staring from zero frequency can be apparently observed, whose cutoff frequency is adjusted by varying the temperature and the magnetic field. However, because of the contribution of the normal conducting electrons (NCEs) , taking no account of external magnetic field, the width of the low frequency photonic band gap (PBG) is no longer influenced by the temperature of the superconductor. The cutoff frequency of PBG adjusted by the temperature and the external magnetic field with the contribution of NCEs are compared with those obtained by neglecting them. However, when superconductors are in a normal state, the low frequency PBG of photonic crystals disappears.