Figure 1

Time domain transmitted THz waveforms when (a) $L=0\mathrm{mm}$, (b) $L=2\mathrm{mm}$, (c) $L=3\mathrm{mm}$, (d) $L=4\mathrm{mm}$, (e) $L=5\mathrm{mm}$, and (f) $L=9\mathrm{mm}$ using the $B$ configuration shown in the inset in (b). (g) The time domain THz transmission through a 2 mm thick Co sample using the $B$ configuration shown in its inset. Transmission measurements made through a 3 mm thick sample of $50\mu \mathrm{m}$ Cu particles are illustrated in (h) for $B_{\parallel }=0.18\mathrm{T}$ and $B=0$ configurations.Reuse & Permissions

Figure 2

(a) The transmission arrival time versus magnetic field through a $L=3\mathrm{mm}$ Co sample. The inset in (a) depicts the integrated spatial profile along the polarization axis of the THz transmission through a Co sample for $B=0\mathrm{T}$, $B_{\perp }=+0.18\mathrm{T}$, and $B_{\perp }=-0.18\mathrm{T}$. The integrated spatial profile of the transmission shows no $B$-polarity-dependent effects. (b) The relative delay versus sample thickness for the $B_{\parallel }=0.18\mathrm{T}$ configuration with respect to $B=0$. (c) Arrival time and (d) peak-to-peak electric field amplitude $|E_{\mathrm{trans}}|$ of the transmitted THz pulse for $B_{\parallel }=0.18\mathrm{T}$ and $B=0\mathrm{T}$ versus sample thickness. The arrival times correspond to velocities of ${\nu }_{g,\parallel }=0.51\pm 0.01\mathrm{c}$ and ${\nu }_{g,0}=0.55\pm 0.01\mathrm{c}$ for $B_{\parallel }=0.18\mathrm{T}$ and $B=0\mathrm{T}$, respectively.Reuse & Permissions

Figure 3

Electric field amplitude images of a finite difference time domain simulation of single-cycle THz pulse excitation of a $70\mu \mathrm{m}$ diameter Co particle at various times. Experimental data from Ref. 19 are used to fit the Drude permittivity $\epsilon (\omega )=1-{\omega }_p^2/(i\Gamma \omega -{\omega }^2)$, where ${\omega }_p=9.8\times {10}^{14}{\mathrm{s}}^{-1}$ and $\Gamma =1.0\times {10}^{13}{\mathrm{s}}^{-1}$ are the plasma and damping frequencies for Co, respectively. As shown in (a), at 6.5 ps the single-cycle TM polarized THz pulse propagates towards the Co particle. At 10 ps, shown in (b), negligible THz field amplitude is present inside the particle due to the large imaginary permittivity at THz frequencies. (c) and (d) show that, after passage of the THz pulse at 15 ps, the fields near the Co particle exhibit strong dipolelike signatures associated with the surface currents at the left and right edges of the particle. The arrows in (a) and (d) depict the orientations of the THz pulse polarization and the net induced dipole in the particle, respectively. In the images, the field amplitude increases from black (0), to blue, to yellow, up to red (1).Reuse & Permissions

Figure 4

Normalized THz electric field amplitude versus $\phi$ and time for (a) $B=0$, (b) $B_{\parallel }$, (c) $B_{\perp }$, and (d) $B_{45}$ configurations. Shown in the side panel is the peak-to-peak THz electric field amplitude versus $\phi$ for $B=0$. The magnetic field in the $B_{\perp }$, $B_{\parallel }$, and $B_{45}$ configurations is 0.18 T.Reuse & Permissions