Figure 2

(a) Temporal change of THz power at 0.6 THz (red plot, left vertical axis) and visible light intensity at 635 nm (green plot, right vertical axis) before and after injection of smoke by burning an incense stick. THz power spectra (b) before (=10 s), (c) during (=35 s) and after (=45 s) burning the incense stick.