基于石墨烯超材料深度可调的调制器

Modulator of Tunable Modulation Depth Based on Graphene Metamaterial

目前人们已经实现了很高的调制深度,但是缺少对如何实现调制深度可调的研究,不利于实现波整形。利用石墨烯的电调谐性以及石墨烯超材料的表面等离激元(SPP)共振特性,设计了一种能够在某一频率实现调制深度可调的调制器,且调制深度为极大值,便于取样及检测,并运用谐振子模型对透射规律进行了理论分析。基于三维电磁场仿真软件时域求解器仿真,得到了对应频率为11.85THz的一系列的调制深度,其中最大调制深度可达到96%以上。这一系列的调制深度可以通过电压调节石墨烯的费米能级来进行调制转换,将极大地促进调制器在波整形中的应用,如生成正弦波、三角波及方波等。此外,这种结构可以实现类电磁感应透明(EIT)现象,不仅能够实现透射峰的频移和展宽,而且可以使展宽前后的中心频率保持一致。

At present, we have achieved a very high modulation depth, but it is unable to realize wave shaping for the lack of research on tunable modulation depth. On the basis of electrical tuning of graphene and the resonance property of graphene metamaterial surface plasmon polaritons （SPP）, a graphene metamaterial modulator of tunable modulation depth at a frequency is proposed and the modulation depth is the maximum value, which is convenient for sampling and testing. The transmission law is theoretically analyzed by using the harmonic oscillator model. Based on the simulation of three-dimensional simulation software time domain solver, the series of modulation depth corresponding to the frequency of lI. 85 THz is ohtained, where the maximum modulation depth is greater than 96~. The series of the modulation depth can be modulated and transformed by bias voltage regulating graphene Fermi level. This will greatly promote the application of modulator in the wave shaping, such as generating sine wave, triangle wave and square wave. In addition, this structure can achieve a similar electromagnetically induced transparency （EIT） phenomenon. It can not only achieve the frequency shift and the transmission peak broadening, but also keep the center frequency the same before and after broading center frequency.