Terahertz time-domain spectroscopy characterization of the far-infrared absorption and index of refraction of high-resistivity, float-zone silicon

The frequency and width of the Lorentz oscillator are very close to those reported in Ref. [45], showing reliability of the method.

“Additionally, both the frequency and the width of the Lorentz oscillator tend to be very close to the one reported in Ref. [45]-showing the reliability of the method.”

Estimating from the sample dimensions, the beam radius in [13] was of the order of 1-2 cm, which provides a Gouy shift correction of the refractive index of approximately 0.5-1 × 10^−4, consistent with the observed decrease in the refractive index in Fig. 4 of [13].

“it is possible to estimate from the sample dimensions that the beam radius was of the order of 1–2 cm, which provides the Gouy shift correction of the refractive index of approximately 0.5–1 × 10−4, a value consistent with the observed decrease in the refractive index in Fig. 4 of [13].”

The retrieved background refractive index of the Si wafer, 3.415, agrees within 1 per mille with the most precise reported value of 3.4175 for high-resistivity silicon.

“The value of 3.415 of the background refractive index of our Si wafer seems to be in a quite good agreement (difference smaller than 1 per mille) with the so far most precise value of 3.4175 reported for high-resistivity silicon [13].”