The MOE Key Laboratory of Weak-Light Nonlinear Photonics, TEDA Applied Physics Institute and School of Physics, Nankai University, Tianjin 300457, China.
Synergetic Innovation Center of Chemical Science and Engineering, Tianjin 300071, China.
Sci Rep. 2016 May 27;6:26796. doi: 10.1038/srep26796.
Tunable band-stop filters based on graphene with periodically modulated chemical potentials are proposed. Periodic graphene can be considered as a plasmonic crystal. Its energy band diagram is analyzed, which clearly shows a blue shift of the forbidden band with increasing chemical potential. Structural design and optimization are performed by an effective-index-based transfer matrix method, which is confirmed by numerical simulations. The center frequency of the filter can be tuned in a range from 37 to 53 THz based on the electrical tunability of graphene, while the modulation depth (-26 dB) and the bandwidth (3.1 THz) of the filter remain unchanged. Specifically, the bandwidth and modulation depth of the filters can be flexibly preset by adjusting the chemical potential ratio and the period number. The length of the filter (~750 nm) is only 1/9 of the operating wavelength in vacuum, which makes the filter a good choice for compact on-chip applications.
基于化学势周期性调制的石墨烯可调带阻滤波器被提出来。周期性石墨烯可以被视为等离子体激元晶体。我们分析了它的能带结构，清楚地显示了禁带随化学势增加而蓝移。我们通过基于有效折射率的传输矩阵方法进行了结构设计和优化，并通过数值模拟进行了验证。滤波器的中心频率可以在 37 到 53 THz 的范围内进行调谐，这基于石墨烯的电可调性，而滤波器的调制深度（-26 dB）和带宽（3.1 THz）保持不变。具体来说，通过调整化学势比和周期数可以灵活预设滤波器的带宽和调制深度。滤波器的长度（约 750nm）仅为真空中工作波长的 1/9，这使得滤波器成为用于片上紧凑应用的良好选择。
