Observation of Narrow-Band Terahertz Coherent Cherenkov Radiation from a Cylindrical Dielectric-Lined Waveguide
Observation of Narrow-Band Terahertz Coherent Cherenkov Radiation from a Cylindrical Dielectric-Lined Waveguide
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DOI：
10.1103/physrevlett.103.095003
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发表时间：
2009-08-28
影响因子：
8.6
通讯作者：
Rosenzweig, J. B.
中科院分区：
文献类型：
--
作者：
Cook, A. M.;Tikhoplav, R.;Rosenzweig, J. B.
我们报告了由亚皮秒电子束驱动的窄带相干切伦科夫辐射的实验观察，该辐射沿着空心圆柱形电介质衬里波导的轴传播。为了适当选择电介质壁厚度，短脉冲束电流分布仅激发结构的基模，产生太赫兹范围内的高能脉冲。我们提供的详细测量结果显示，横向尺寸为亚毫米的 1 厘米长熔融石英毛细管的窄发射光谱峰值为 367 +/- 3 GHz，与预测非常吻合。我们证明，当管壁厚度改变 50 μm 时，发射的中心频率会发生 100 GHz 的偏移。辐射能量的校准测量表明，对于 200 pC 的入射束电荷，每 60 ps 脉冲高达 10 μJ，对应于约 150 kW 的峰值功率。
We report experimental observation of narrow-band coherent Cherenkov radiation driven by a subpicosecond electron bunch traveling along the axis of a hollow cylindrical dielectric-lined waveguide. For an appropriate choice of dielectric wall thickness, a short-pulse beam current profile excites only the fundamental mode of the structure, producing energetic pulses in the terahertz range. We present detailed measurements showing a narrow emission spectrum peaked at 367 +/- 3 GHz from a 1 cm long fused silica capillary tube with submillimeter transverse dimensions, closely matching predictions. We demonstrate a 100 GHz shift in the emitted central frequency when the tube wall thickness is changed by 50 mu m. Calibrated measurements of the radiated energy indicate up to 10 mu J per 60 ps pulse for an incident beam charge of 200 pC, corresponding to a peak power of approximately 150 kW.