Publications by authors named "Tianhao Xia"

Terahertz (THz) radiation from air plasma in the presence of pre-plasma in a collinear geometry is investigated experimentally, where the pre-plasma is formed by a pre-pulse with a Gaussian beam profile and the measured THz radiation is driven by a main laser pulse. The pre-plasma has a de-focusing effect for the main pulse passing through it, which reduces the effective length of the plasma filament formed by the main laser pulse for THz radiation. It is found that only the part not overlapped by the pre-plasma can actually produce THz radiation.

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Patients with diffuse large B-cell lymphoma (DLBCL) have unsatisfactory outcomes, especially when relapse occurs after initial chemotherapy. Platycodin D (PD), a triterpenoid saponin isolated from the root of Platycodon grandiflorum (Jacq.) A.

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Detection and manipulation of radially polarized terahertz (THz) radiation is essential for many applications. A new measurement scheme is proposed for the diagnosis of radially polarized THz radiation from a longitudinal dc-biased plasma filament, by introducing a movable metal mask. The amplitude and spectrum of the radially polarized THz beam was measured with a <110>-cut ZnTe crystal, where the THz beam pattern was modulated by the mask.

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The phase evolution of terahertz (THz) radiation from single-color femotsecond laser-induced air plasma controlled by a DC-bias is investigated experimentally. When the DC-bias is moved from the end to the beginning of the laser plasma filament, the produced THz waveform is advanced temporally, and its carrier-envelope phase is changed. Our phase spectrum analysis suggests that the slope and the intercept of the phase spectrum, respectively, determine the temporal shift and the carrier-envelope phase of the THz waveform.

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