Abstract-High-responsivity and polarization-discriminating terahertz photodetector based on plasmonic resonance

Applied Physics Letters

Yuanliao Zheng, Pingping Chen, Heming Yang, Jiayi Ding, Yuwei Zhou, Zhou Tang, Xiaohao Zhou, Zhifeng Li, Ning Li,  Xiaoshuang Chen, Wei Lu,

(a) The structure of the SPQWP device; (b) the schematic view of the periodic units for the SPQWP structure

https://aip.scitation.org/doi/abs/10.1063/1.5085813

In this paper, a high-responsivity terahertz quantum well photodetector based on plasmonic resonance is proposed and investigated theoretically and experimentally, and the polarization-discriminating detection of the device is demonstrated. With a one-dimensional metallic grating structure integrated on the top of the detector, a 6-fold enhancement of the peak responsivity about 0.82 A/W at 46 μm compared to that of the standard device has been achieved. The physical mechanism behind the enhanced responsivity can be attributed to the enhancement of the intersubband absorption resulting from the surface Plasmon polariton mode, which can be explored from the theoretical simulation results. The polarization extinction ratio of the plasmonic-enhanced device reaches 56, and the measured signal intensity at each polarization angle satisfies Malus' law. In addition to the above advantages, the structure is simple in fabrication and compatible with the preparation process of the focal plane array. The results open up an effective method for the application of surface plasmon in terahertz detection.

Abstract-Highly Sensitive and Wide-Band Tunable Terahertz Response of Plasma Waves Based on Graphene Field Effect Transistors

• Lin Wang,
• Xiaoshuang Chen,
• Anqi Yu,
• Yang Zhang,
• Jiayi Ding
• & Wei Lu

• Affiliations
• Contributions
• Corresponding author

http://www.nature.com/srep/2014/140627/srep05470/full/srep05470.html

Scientific Reports

 

4,

 

Article number:

 

5470

 

doi:10.1038/srep05470

Received

 

30 January 2014 

Accepted

 

27 May 2014 

Published

 

27 June 2014

Terahertz (THz) technology is becoming a spotlight of scientific interest due to its promising myriad applications including imaging, spectroscopy, industry control and communication. However, one of the major bottlenecks for advancing this field is due to lack of well-developed solid-state sources and detectors operating at THz gap which serves to mark the boundary between electronics and photonics. Here, we demonstrate exceptionally wide tunable terahertz plasma-wave excitation can be realized in the channel of micrometer-level graphene field effect transistors (FET). Owing to the intrinsic high propagation velocity of plasma waves (>~10⁸ cm/s) and Dirac band structure, the plasma-wave graphene-FETs yield promising prospects for fast sensing, THz detection, etc. The results indicate that the multiple guide-wave resonances in the graphene sheets can lead to the deep sub-wavelength confinement of terahertz wave and with Q-factor orders of magnitude higher than that of conventional 2DEG system at room temperature. Rooted in this understanding, the performance trade-off among signal attenuation, broadband operation, on-chip integrability can be avoided in future THz smart photonic network system by merging photonics and electronics. The unique properties presented can open up the exciting routes to compact solid state tunable THz detectors, filters, and wide band subwavelength imaging based on the graphene-FETs.