共查询到19条相似文献,搜索用时 46 毫秒
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太赫兹混频器可通过本征信号与原信号混合,经频率变换,实现频谱探测、超分辨成像和天文信号高灵敏探测,在太赫兹频谱识别、太赫兹安检、射电天文探测等领域具有重要应用前景。本文首先介绍了太赫兹混频器的基本原理、分类、主流技术方案;其次针对太赫兹混频器超灵敏化、高频化、中频宽带化和小型化集成的应用需求,分析了国内外太赫兹混频器设计与制作技术的发展动态;最后归纳了太赫兹混频器的应用状况、技术挑战和可能的解决方案,以便阐明三类太赫兹混频器的技术特点和技术发展趋势。 相似文献
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随着无线通信技术的发展,对无线通信速率和频率的要求逐年提高。现有无线通信频段已趋于饱和,而太赫兹频段是一个全新的空间。本文按照产生方式分类对近年国内外太赫兹通信研究最新进展进行了综述,并给出未来太赫兹通信系统在光载无线通信、空间领域、军事领域上的可能应用方向。 相似文献
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太赫兹脉冲整形技术研究进展 总被引:1,自引:0,他引:1
太赫兹(THz)脉冲整形技术在量子理论、生物医学成像、安全检查、亚毫米波通信等领域都具有重要的学术价值和应用前景。概述了基于飞秒脉冲的整形技术和新型太赫兹辐射材料整形技术,分析了太赫兹脉冲整形器件整形技术目前的研究状况,并对各种整形方法的发展进行了展望。 相似文献
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为实现太赫兹辐射特性精准认知,开展太赫兹辐射绝对强度测量研究。通过光学频率梳产生太赫兹频率梳,利用太赫兹频率梳实现太赫兹辐射源空间强度测量。本文利用电光采样和光电导探测两种方式,实现了100 GHz辐射源空间辐射强度测量;将100 GHz辐射总功率溯源到标准太赫兹功率计,实现太赫兹辐射强度绝对测量。分析比较了利用800 nm空间光进行电光采样和利用1550 nm光纤激光进行光电导探测的测量结果。本文在不同距离下,对太赫兹辐射源的空间辐射绝对强度进行了测量,实验揭示了太赫兹辐射传输的空间演化特性。 相似文献
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Y. J. Guo S. K. Barton 《International Journal of Satellite Communications and Networking》1994,12(4):381-385
The theory of offset Fresnel zone plate antennas is presented. Explicit formulae for the design of the zone boundaries for the offset Fresnel zone plate are given. Theorectical equations and numerical results for the far-field analysis are presented. It is found that when the offset angle increases, the zone boundaries become more elliptic and the plate becomes more asymmetric in the E-plane. With the number of full wave zones and the plate width in the W-plane fixed, the plate width in the E-plane increases with the offset angle, which keeps the projected aperture area constant. Within a limited range of offset angles, the offset configuration can be employed without degrading the radiation performance much. For large offset angles, however, the asymmetry of the configuration may lead to increased sidelobes and decreased antenna directivity. An experiment with one particular phase reversal zone plate antenna with 30° offset angle shows good agreement between the measured antenna pattern and the theoretical prediction. 相似文献
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采用模拟退火算法设计了0.2~2.0THz和0.2~3.0THz两个波段下的消色差复合太赫兹λ/4波片,在0.2~2.0THz波段内实现了波片相位延迟偏差小于2%,在0.2~3.0THz波段内波片相位延迟偏差小于4%。系统分析了不同石英玻片个数对消色差复合太赫兹波片的消色差性能以及厚度和损耗等关键参量的影响。分析表明,随着石英玻片个数的增加,波片的消色差性能也会变好,在相应太赫兹波段相位延迟失谐量也随之减小;但同时,波片的厚度也随之增加,导致对太赫兹波的损耗增加。在0.2~2.0THz和0.2~3.0THz范围内,太赫兹λ/4波片采用5个玻片为最佳,此时可以获得较好的消色差性能,同时波片的厚度和损耗也在可实际应用范围内。 相似文献
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Seung‐Heon Lee Bong Joo Kang Ba‐Wool Yoo Seung‐Chul Lee Seung‐Jun Lee Mojca Jazbinsek Hoseop Yun Fabian Rotermund O‐Pil Kwon 《Advanced functional materials》2017,27(14)
For terahertz (THz) wave generators based on organic electrooptic crystals, their intrinsic phonon modes are playing an essential role in THz generation characteristics. Here, this study proposes an effective design strategy for THz phonon mode engineering of organic electrooptic salt crystals for efficient optical‐to‐THz frequency conversion. To reduce phonon‐mode intensity, strongly electronegative trifluoromethyl group acting as strong hydrogen‐bond acceptor is incorporated into molecular anions. New 2‐(4‐hydroxy‐3‐methoxystyryl)‐1‐methylquinolinium 4‐(trifluoromethyl)benzenesulfonate (HMQ‐4TFS) crystals exhibit a relatively small absorption coefficient in the THz spectral range between 0.5 and 4 THz, which is attributed to suppressed molecular vibrations due to strong hydrogen bonds involving the 4TFS anion. In addition, HMQ‐4TFS crystals possess a very large macroscopic optical nonlinearity, comparable (or even higher) to benchmark stilbazolium crystals. Based on the low‐intensity THz phonon modes and the large optical nonlinearity, a 0.37 mm thick HMQ‐4TFS crystal pumped with 150 fs infrared laser pulses facilitates very efficient THz wave generation by optical rectification, delivering 23 times higher peak‐to‐peak THz electric field than the widely used standard inorganic ZnTe crystal (1.0 mm thick) and a broader spectral bandwidth. Therefore, strongly electronegative groups introduced into molecular salt electrooptic crystals provide a very promising design strategy of THz phonon mode engineering for developing intense broadband THz sources. 相似文献
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Y. J. Guo S. K. Barton 《International Journal of Satellite Communications and Networking》1993,11(2):75-80
Owing to its flat nature and light weight etc., the Fresnel zone plate antenna is becoming very attractive for such applications as DBS reception and receive-only VSAT. The disadvantages of low efficiency and high sidelobes of the simple and the phase reversing zone plates can be improved by using phase correcting techniques. In this paper, a systematic investigation on the efficiency and sidelobe performance of subzone phase correcting zone plate antennas is presented. The design of a form of multilayer phase correcting zone plate reflector is described. A quarter-wave zone plate reflector constructed with three dielectric layers and metallized rings is reported, with measured peak efficiency of 55 per cent. 相似文献
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Terahertz Generators: Terahertz Phonon Mode Engineering of Highly Efficient Organic Terahertz Generators (Adv. Funct. Mater. 14/2017) 下载免费PDF全文
Seung‐Heon Lee Bong Joo Kang Ba‐Wool Yoo Seung‐Chul Lee Seung‐Jun Lee Mojca Jazbinsek Hoseop Yun Fabian Rotermund O‐Pil Kwon 《Advanced functional materials》2017,27(14)