Sensing Multiwall Carbon Nanotube Film Mediated by a Fano Resonant Terahertz Metasurface
Shreeya Rane, Saloni Sharma, Soumyajyoti Mallick, Nityananda Acharyya, Sharon J. Paul, Shubhda Srivastava, Bipin Kumar Gupta, Dibakar Roy Chowdhury
Abstract
Multiwalled carbon nanotubes (MWCNTs) synthesized via the chemical vapor deposition technique contain metal catalysts that restrict their applications in the terahertz (THz) regime because of strong absorption of THz radiations. To resolve this issue, we have adopted a unique CVD-based synthesis approach to remove the metal catalysts from the synthesized MWCNTs. Moreover, we have studied the optical parameters of the MWCNT film by employing THz-TDS. To explore the MWCNTs in terahertz photonic devices, we have demonstrated sensing of an MWCNT film utilizing a Fano- resonance-based metasurface. Our studies demonstrate MWCNT sensitivity as high as 8 GHz/RIU with an FoM (figure of merit) value as 89.71 while operating at the Fano mode. Hence, these findings could open up a range of possibilities for practical applications of MWCNTs (low-dimensional materials) in the emerging fields of THz nanophotonics.