High speed Imaging with High Power Terahertz Pulses

高功率太赫兹脉冲高速成像

• 批准号: 13450026
• 负责人: HATTORI Toshiaki
• 金额: $ 9.79万
• 依托单位: University of Tsukuba
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13450026/
• 关键词: terahertz; imaging; electro-optic sampling; diffraction integral; heterodyne; GaAs; InP; electron dynamics; フェムト秒; 高速撮影; ガウスビーム

High power terahertz (THz) electromagnetic pulses were generated using 1-kHz-repetition-rate high power femtosecond laser pulses, and the following results were obtained for the achievement of high speed THz imaging. High speed THz imaging was achieved by using a large (2 cm × 2 cm) electro-optic crystal and probe beam and acquiring the images with a CCD camera. Sufficiently good image quality was obtained with 30-ms accumulation. Using the present setup, spatio-temporal intensity profile on and near the focal plane was obtained, which showed for the first time an annular distribution of the THz intensity. Simulations based on diffraction integral and the Gaussian beam model showed that this phenomenon is specific for the half-cycle THz pulses. Direct observation of the THz electric field was achieved by applying the optical heterodyne detection method, which enabled better sensitivity and frequency-resolved spatial distribution studies. By observing the pump wavelength dependence of the THz waveforms emitted from GaAs and InP antennas, ultrafast intraband electron dynamics in these materials was studied.

利用1 khz重复频率的高功率飞秒激光脉冲产生高功率太赫兹（THz）电磁脉冲，为实现高速太赫兹成像获得了以下结果：采用大（2cm × 2cm）的电光晶体和探针光束，利用CCD相机采集图像，实现了高速太赫兹成像。积累30ms即可获得足够好的图像质量。利用该装置，获得了焦平面上和焦平面附近的时空强度分布图，首次显示了太赫兹强度的环形分布。基于衍射积分和高斯光束模型的模拟表明，这种现象只存在于半周太赫兹脉冲中。采用光学外差检测方法实现了对太赫兹电场的直接观测，提高了对太赫兹电场的灵敏度和频率分辨空间分布的研究。通过观察GaAs和InP天线发射的太赫兹波的泵浦波长依赖性，研究了这些材料中的超快带内电子动力学。

项目成果

H.Inouye et al.: "Ophcal properties of a total-reflection-type care-dimensional photonic"IEEE J.Quant.Electron.. 38・7. 867 (2002)

H. Inouye 等：“全反射型护理维光子的光学特性” IEEE J. Quant. 38・7 (2002)。

R.Rungsawang et al.: "Ring formetion of focused half-cyde terahertz pulses"J.Phys.D. 36・3. 229 (2003)

R. Rungsawang 等：“聚焦半周期太赫兹脉冲的环形成”J.Phys.D 36・3（2003）。

T.Hattori et al.: "Liquid-crystal phase transition probed by flucrescent molecules"Jpn. J. Appl. Phys.. 40. 4928-4932 (2001)

T.Hattori 等：“荧光分子探测液晶相变”Jpn。

T.Hattori: "Third-order nonlinearity enhancement in one-dimensional photonic crystal structures"Jpn.J.Appl.Phys.. 41(3A). 1349-1353 (2002)

T.Hattori：“一维光子晶体结构中的三阶非线性增强”Jpn.J.Appl.Phys.. 41(3A)。

T.Hattori et al.: "Time-resolved study of intense terahertz pulses generated by a large-aperture photoconductive antenna"Jpn. J. Appl. Phys.. 40. 4907-4912 (2001)

T.Hattori 等人：“大孔径光电导天线产生的强太赫兹脉冲的时间分辨研究”Jpn。