Optical effective mass of photon in single and bilayer graphene in 10Â MHz-26.5Â GHz frequency range

The present study has been carried out to experimentally determine the optical effective mass of photon in single layer graphene transferred on glass and quartz substrates, and bilayer graphene as-grown on Cu foil. Measurements have been performed in microstrip line based test fixture where first real and imaginary parts of complex relative permittivity have been obtained, then the refractive index is used to estimate the phase velocity in single and bilayer graphene, this index were found to be higher at lower frequency below 1.5 GHz. The phase velocities are found to be ∼ 1.04 × 108 ms−1 and ∼ 1.11 × 108 ms−1 in single and bilayer graphene, respectively and little high group velocities are found in range of 2-26.5 GHz. In single and bilayer graphene, the optical effective mass has been found to vary from ∼ 0.72 × 10−10m0 to ∼ 0.2 × 10−8m0 in a frequency range between 1 and 26.5 GHz. We envision that reported results can help to understand the transport behaviour of photons in as-grown graphene layer in microwave frequency range.

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