Single-walled carbon nanotubes assisted THz silicon grating modulator.

Single-walled carbon nanotubes (SWCNTs) are applied to realize an enhanced frequency modulation for a suspended THz silicon grating, which is fabricated by a nanosecond laser direct writing and coated with the synthetic SWCNTs/polyacrylic emulsion composite. With terahertz time domain spectroscopy system, the transmission spectra of the bare and SWCNTs coated silicon grating are measured and compared. The SWCNTs coated silicon grating can realize an improved extinction ratio and quality factor, which is due to the SWCNTs caused local field enhancement and can be explained by the theoretical simulation with finite element method. Besides the effective modulation of the grating transmittance, SWCNTs can also be integrated with other platforms and applied in future THz imaging and communication systems.