Enhanced Measurement of Paper Basis Weight Using Phase Shift in Terahertz Time-Domain Spectroscopy

Figure 3

Schematic diagram of the THz-TDS experimental system. BS: beam splitter, PM: parabolic mirror, HWP: half-wave plate, QWP: quarter-wave plate, WP: Wollaston prism, BL: balanced photodiode, A: aperture, and M: mirror.