We measure field enhancement through nanogap by using both terahertz time domain spectroscopy (TDS) and terahertz imaging technique with continuous wave (CW) radiation source. Far-field amplitude is connected to the near-field enhancement through the Kirchhoff formalism [1, 2, 3]. With TDS, we found that a field enhancement of 200 at 0.1THz for the 500nm slit. To confirm our TDS results, we also perform the transmission experiment with 70nm width nanogap structure perforated in thin gold films on Si substrates by using 0.2THz CW source.
展开▼
