Terahertz Time-Domain Spectroscopy for Material Characterization

Self-biased reconfigurable graphene stacks for terahertz plasmonics

“…The sample is measured in the 0.5-2.5 THz frequency range using time-domain spectroscopy. The complex conductivity of the graphene stack is then retrieved using a dedicated formulation 8,35,36 . Details regarding the fabrication, measurement and stack conductivity extraction process are provided in Methods.…”

“…The stack conductivity s S is extracted from the THz time-domain measurements, using standard thin-film characterization techniques 8,35,36,58 . This approach is valid here, thanks to the extreme fineness of the stack in terms of wavelength (d/lo o10 À 3 ).…”

“…(ii) A pulse is transmitted through an area of the sample free of graphene, which remains bare. The combination of this measured pulse with the pulse obtained in the previous step allows the extraction of the permittivity, loss tangent and thickness of the dielectrics using standard techniques 36,58 . (iii) A pulse is transmitted through the graphene stack sample.…”

“…(iii) A pulse is transmitted through the graphene stack sample. Combining this measured pulse with the previous information, it is indeed possible to extract the conductivity of the graphene stack rigorously removing the influence of the dielectrics and surrounding atmosphere 8,35,36 .…”

Development of planar Goubau line - microfluidic integrated devices for THz spectroscopy of liquid analytes

“…The quartz permittivity was taken to be 3.8 [9], and so in regions I and III where the superstrate was air, ε eff was approximately 2.4. The permittivity of PDMS was taken to be 2.35 [10], resulting in an ε eff for region II of approximately 3.3.…”