Abstract-Giant dual-mode graphene-based terahertz modulator enabled by Fabry–Perot assisted multiple reflection

Pei-Ren Tang, Jiang Li, Sen-Cheng Zhong, Zhao-Hui Zhai, Bing Zhu, Liang-Hui Du, Ze-Ren Li, Li-Guo Zhu

https://www.osapublishing.org/ol/abstract.cfm?uri=ol-44-7-1630

We report a high-performance terahertz (THz) modulator with dual operation mode. For the pulse operation mode, the proposed THz modulator has the advantage of high modulation depth (MD) and can operate in a broadband frequency range. We have experimentally achieved a MD larger than 90% for the fifth-order pulse THz echo at 0.8 THz, and the MD stays larger than 75% in a broadband frequency range larger than 1 THz, whereas, for the coherent operation mode, the Fabry–Perot (F-P) interference effect has been taken into consideration and a MD larger than 75% at 0.76 THz has also been realized.

© 2019 Optical Society of America

Abstract-Ultrasensitive specific terahertz sensor based on tunable plasmon induced transparency of a graphene micro-ribbon array structure

Pei-ren Tang, Jiang Li, Liang-hui Du, Qiao Liu, Qi-xian Peng, Jian-heng Zhao, Bing Zhu, Ze-ren Li, Li-guo Zhu,

Fig. 1 Conceptual view of the PIT-sensor based on graphene micro-ribbon (GMR). The electromagnetic field is mainly concentrated at the edges of GMR, when excited by a THz wave, leading to the enhanced interaction between THz wave and the analyte. The tunability of the PIT sensor is achieved by changing the bias voltages (V1 and V2) applied on the two sets of GMR arrays.

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-26-23-30655

We proposed an ultrasensitive specific terahertz sensor consisting of two sets of graphene micro-ribbon with different widths. The interference between the plasmon resonances of the wide and narrow graphene micro-ribbons gives rise to the plasmon induced transparency (PIT) effect and enables ultrasensitive sensing in terahertz region. The performances of the PIT sensor have been analyzed in detail considering the thickness and refractive index sensing applications using full wave electromagnetic simulations. Taking advantage of the electrical tunability of graphene’s Fermi level, we demonstrated the specific sensing of benzoic acid with detection limit smaller than 6.35 µg/cm2. The combination of specific identification and enhanced sensitivity of the PIT sensor opens exciting prospects for bio/chemical molecules sensing in the terahertz region.

© 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement