Fig. 6

Terahertz time-domain spectrum for (a) the bare substrate and micro-nano metal metasurface for 300, 500 and 700 °C heat treatment. (b–d) Air reference and GAF for 300 °C (b), 500 °C (c) and 700 °C (d) heat treatment.

Terahertz time-domain spectrum for (a) the bare substrate and micro-nano metal metasurface for 300, 500 and 700 °C heat treatment. (b–d) Air reference and GAF for 300 °C (b), 500 °C (c) and 700 °C (d) heat treatment.