Figure 1

Experimental schematic of the four different pump-probe polarization configurations used in the experiment.Reuse & Permissions

Figure 2

(Color online) Dependence of static THz absorption (solid squares) as a function of angle between THz-wave polarization and the stretched axis with $0°$ corresponding to parallel case as shown in Fig. 1a and $90°$ corresponding to perpendicular case as shown in Fig. 1c. The solid line is a fitting curve. Blank squares are the data for unaligned SWNTs.Reuse & Permissions

Figure 3

(Color online) (a) Dependence of the optically induced differential transmission (solid squares) as a function of angle between THz-wave polarization and the stretched SWNTs axis while keeping pump polarization parallel to the stretched SWNTs axis. Here $0°$ corresponds to the parallel case shown in Fig. 1a and $90°$ corresponds to the perpendicular case as shown in Fig. 1d. The solid line is a fitting curve. (b) Absorption anisotropy measured at 800 nm.Reuse & Permissions

Figure 4

(Color online) (a) Ultrafast responses for different pump-probe configurations corresponding to the four different pump-probe polarization configurations in Fig. 1. (b) Ultrafast responses deduced for optical and THz fields aligned precisely parallel and perpendicular to the nanotube axes as described in the text. The inset shows the longer time length dynamic responses. (c) Transient polarization as a function of time after photoexcitation for the pump polarization parallel (red) $P_{\parallel }$ and perpendicular (black) $P_{\perp }$ to the axis of the SWNTs.Reuse & Permissions