Negative and Superluminal Group Velocity Propagation with Narrow Pulse in a Coaxial Photonic Crystal  

作　　者：偶晓娟 周渭 李琳 滕李虎 冯宝英 郑胜峰 王凤伟 

机构地区：[1]Department of Measurement and Instrument, Xidian University, Xi'an 710071

出　　处：《Chinese Physics Letters》2007年第3期624-627,共4页中国物理快报（英文版）

基　　金：Supported by the National Natural Science Foundation of China under Grant No 60571060.

摘　　要：We investigate the propagation of electric signal along a spatially periodic impedance mismatched transmission line group. Anomalous dispersion is caused by the periodically mismatched impedance structure and a forbidden band appears near 8 MHz in transmission. The group velocity of the amplitude-modulated signal is augmented up to infinity, even -3.89c （c the speed of light in vacuum） in the forbidden region with the amplitude of the modulated signal increasing. When the carrier sinusoid signal is modulated in amplitude by the modulating sinusoid signal, of which the peak is superimposed with a narrow pulse at fivefold frequency, the superluminal group velocity also occurs. The experiment failed to show whether the propagation velocity of narrow pulse exceeds c or not.We investigate the propagation of electric signal along a spatially periodic impedance mismatched transmission line group. Anomalous dispersion is caused by the periodically mismatched impedance structure and a forbidden band appears near 8 MHz in transmission. The group velocity of the amplitude-modulated signal is augmented up to infinity, even -3.89c （c the speed of light in vacuum） in the forbidden region with the amplitude of the modulated signal increasing. When the carrier sinusoid signal is modulated in amplitude by the modulating sinusoid signal, of which the peak is superimposed with a narrow pulse at fivefold frequency, the superluminal group velocity also occurs. The experiment failed to show whether the propagation velocity of narrow pulse exceeds c or not.

分 类 号：O43[机械工程—光学工程]