共查询到20条相似文献,搜索用时 656 毫秒
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C. S. Kou J. Y. Huang C. M. Tsai 《International Journal of Infrared and Millimeter Waves》1999,20(5):897-911
A slot antenna is developed to excite the high harmonic waveguide mode for generating large-area plasmas. This antenna consists of a TE011 mode coaxial cavity with the axial slots positioned on equal interval on the inner wall. The waves radiated from those slots can excite the high harmonic mode in the central area. With the azimuthal symmetric wave field of the TE011 mode, the number of the slots can be chosen to match the field pattern of the high harmonic mode. In this report, the dispersion relation of the coaxial waveguide, the coupling scheme and the mode competition of the cavity are studied. A method has been successfully developed to suppress the TE121 mode which is the most competing mode to the TE011 mode. 相似文献
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Analytical solution of the fundamental space filling mode of photonic crystal fibers 总被引:1,自引:0,他引:1
Yan-feng Li Ching-yue Wang Zi-han Wang Ming-lie Hu Lu Chai 《Optics & Laser Technology》2007,39(2):322-326
Analytical solution of the fundamental space filling mode of photonic crystal fibers is revisited based on previous results by Midrio et al. [J Lightwave Technol 2000;18(7):1031–7]. The fundamental space filling mode is designated HE11 mode following the conventional mode classification. A comparison is made between the vectorial method and the scalar method when identical parameters are used in the analytical solution. A more accurate radius of the equivalent circular unit cell is determined. 相似文献
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In this paper,experimental and theoretical studies of the output mode characteristics of an in-phase locked gain waveguide array CO 2 laser are reported.The experimental results of the optical oscillation mode frequency,the far-field intensity distribution and the burnt pattern of the sliced waveguide array laser are obtained.A revised mode expression of the rectangle waveguide,which is suited for this waveguide array CO 2 laser,is proposed.The theoretical simulation results based on the revised mode expression are shown to be in good agreement with the experimental results. 相似文献
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Conclusion Mode competition — interaction between a mode and another mode — is due to the non-linearity of the relativisitc factor . At the beginning of a multimode oscillating, the behavior of the multimode oscillating is only dependent on the ratio of mode frequency and relativistic cyclotron frequency and is in agreement with that described by single mode theory. In non-linear domain mode interaction depends on both amplitudes of A1 and A2 and phase difference i of the two modes. The main effect of mode interaction is that excitation of the parasitic mode suppresses growth of the operating mode.Under the operating conditions with high efficiencies, a mode interaction between the dominant mode and the lower lateral mode is almost unavoidable, especially in the gyrotron operating with a cavity at higher order modes to increase the capability of output power.A research fellow of the Alexander von Humboldt Foundation coming from Beijing Vacuum Electron Devices Research Institute, Beijing, China 相似文献
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Mary C. Frawley Alex Petcu-Colan Viet Giang Truong Síle Nic Chormaic 《Optics Communications》2012,285(23):4648-4654
The propagation of higher modes, such as the LP11 mode, in optical nanofibers using the exponentially tapered optical fiber as a basic model is investigated. In order to preserve the LP11 mode in the downtaper as far as the nanofiber waist, the effect of varying the cladding-core radius ratio on the LP11 adiabatic criterion is modeled. A Laguerre-Gaussian beam is created in free space using a spatial light modulator (SLM) and coupled to a few-mode fiber. This device allows convenient switching between the fundamental and LP11 fiber modes. By selecting a few-mode fiber with a relatively low cladding-core ratio, the propagation of the LP11 mode down to a submicron waist has been maintained. Furthermore, by observing the transmission profile during tapering, it is possible to decisively terminate the pulling process in order to eliminate the two degenerate HE21 modes of the LP11 mode. As a result, a nanofiber can be fabricated through which only the TE01 and TM01 components of the LP11 mode propagate. Such a nanofiber has promising applications in the area of mode interference for controlled particle trapping sites. 相似文献
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本文讨论了三种不同系统的小孔耦合的近似解法:矩形波导与圆柱波导的同轴耦合,矩形波导中的TE10型波与圆柱谐振腔中的TM120型波间的耦合和矩形波导中的TE10型波与圆柱波导中的TMmn型波间的耦合。通过这几个问题的解法,我们希望读者可以看到处理复杂微波元件问题时所需的从物理概念出发的灵活应用已有方法的必要性。这里提供的几个公式有着广泛的应用范围而是在现有文献中探讨得不够的。这里介绍的方法可以应用到其他新的微波网络问题中去。 相似文献
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HEM11 mode magnetically insulated transmission[2mm] line oscillator: simulation and experiment 下载免费PDF全文
Wang Dong Qin Fen Wen Jie Chen Dai-Bing Jin Xiao An Hai-Shi Zhang Xin-Kai 《中国物理 B》2012,21(8):84101-084101
A novel magnetically insulated transmission line oscillator (MILO) in which a modified HEM11 mode is taken as its main interaction mode (HEM11 mode MILO) is simulated and experimented in this paper. The excitation of the oscillation mode is made possible by carefully adjusting the arrangement of each resonant cavity in a two-dimensional slow wave structure. The special feature of such a device is that in the slow-wave-structure region, the interaction mode is HEM11 mode which is a TM-like one that could interact with electron beams effectively; and in the coaxial output region, the microwave mode is TE11 mode which has a favourable field density pattern to be directly radiated. Employing an electron beam of about 441 kV and 39.7 kA, HEM11 mode MILO generates a high power microwave output of about 1.47 GW at 1.45 GHz in particle-in-cell simulation. The power conversion efficiency is about 8.4 % and the generated microwave is in a TE11-like circular polarization mode. In a preliminary experiment investigation, high power microwave is detected from the device with a frequency of 1.46 GHz, an output energy of 43 J-47 J, and a pulse duration of 44 ns-49 ns when the input voltage is 430 kV-450 kV, and the diode current is 37 kA-39 kA. 相似文献
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Yin Li Chongqing Jiao Jirun Luo 《International Journal of Infrared and Millimeter Waves》2007,28(12):1155-1160
A mode converter with multi-waveguide output for millimeter wave gyro-device applications is proposed in this article, which
is used to convert the TE01 circular waveguide mode into the TE10 rectangular waveguide mode. Computer simulations with Ansoft HFSS code show that the energy transmission coefficient of larger
than 95.96% may be reached in the frequency range from 34.094 GHz to 35.8 GHz (a bandwidth of 1.706 GHz) at a VSWR of lower
than 1.5 for the input operating mode. 相似文献
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B. A. Ivanov P. V. Bondarenko A. Yu. Galkin C. E. Zaspel D. D. Sheka 《Bulletin of the Russian Academy of Sciences: Physics》2007,71(11):1494-1496
A low-frequency (the frequency ωVPM is in the sub-GHz range) mode exist for submicron magnetic particles in the vortex state. This mode corresponds to oscillations of the vortex center. The other modes form doublets with higher (several gigahertz) frequency and small (about ωVPM) splitting. Collective oscillations exist for lattices of such particles. The dependence of the frequency of these modes on the quasi-momentum can be nonanalytic. 相似文献
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Abstract We have investigated the effect of pressure on lattice parameters and Raman-active phonons of the molecular crystal xenon difluride by powder x-ray diffraction and first-order Raman scattering, respectively. The ambient pressure tetragonal crystal structure remains stable up to the maximum pressure of 50 GPa. The compressibility is found to be strongly anisotropic. The frequencies of the intramolecular A1g stretching mode and the Eg libration increase sublinearly under pressure. ding the a-and c-axis compression data, we have determined the dependence of phonon frequencies on lattice parameters. The high-frequency A1g mode shows a pronounced nonlinear scaling with c-axis lattice parameter, with particularly small changes during initial compression. This effect is attributed to the interplay between intra-and intermolecular interactions during compression 相似文献
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R. Minami A. Kasugai K. Takahashi N. Kobayashi Y. Mitsunaka K. Sakamoto 《International Journal of Infrared and Millimeter Waves》2006,27(1):13-24
A high efficiency launcher of quasi-optical (QO) mode converters for high power gyrotrons have been designed and tested. A
helical cut launcher radiates the RF power via its straight cut onto the first phase correcting mirror. The launchers have
been optimized for the TE31.8 mode at 170 GHz and TE22.6 mode at 110 GHz by numerically optimizing a launcher surface. The helical cut of the launcher has been optimized by taking
the taper angle into account. Further more, the amplitude of the surface perturbation have been optimized for improved focusing
in order to reduce the diffraction losses at the helical cut. Low power measurement shows a good agreement with the design.
High efficiency characteristics of the design have also been calculated on the assumption of frequency downshift due to the
thermal expansion of the cavity and stepwise frequency tuning by changing the operating mode. Besides, the possibility of
high efficiency launcher for higher mode is discussed, and these results give the prospect to high efficiency long pulse gyrotrons. 相似文献
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A simple extension to the technique of “pre-lase” Q-switching ensures that a TEM00 mode, Q-switched NdYAG laser produces single longitudinal mode oscillation on every shot. 相似文献
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S.M. Rezende Cid.B. de Araujo E. Montarroyos V. Jaccarino 《Solid State Communications》1980,35(8):627-630
A study of the local magnon mode in FeF2 crystals with Mn2+ impurities by inelastic Raman light scattering is presented. Though the interaction between the radiation and the Mn spins is negligible the scattering by the s0 local mode is very strong. The data of the frequency and the scattering intensity are analyzed in terms of a magnetization coupled mode approach. 相似文献
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Qian-Zhong Xue Shi-Chang Zhang Pu-Kun Liu 《International Journal of Infrared and Millimeter Waves》2005,26(10):1407-1415
A design procedure for the H10□ to H01° sector-type mode converter at Ka-band is described in detail. As an example, an H10□ to H01° sector-type mode converter with an input rectangular port size as 7.112×3.556 mm2 and another output circular port diameter as 17.2 mm is designed and measured for insertion losses and wanted mode pattern.
The mode converting efficiency from H10□ mode to H01° mode is about 91.2%. The insertion losses of the converter are lower than 0.1525 dB with 2GHz band. 相似文献
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利用超快泵浦探测红外光谱、稳态线性红外光谱和计算化学方法,对过渡金属羰基化合物Mn(CO)5Br和Re(CO)5Br的振动和结构动力学进行了研究. 借助羰基的两个伸缩振动峰(处于低频的A1模式和处于高频的简并E模式)进行了观测. 结果表明,在两个配合物中,A1和E模式振动峰的振动频率位置及频率差都与中心金属原子对羰基的键级和振动力常数的影响相关. 而A1模式比E模式的线宽宽一些,部分由于振动寿命的影响. 此外,从瞬态光谱中获得了振动模式依赖的对角非谐性常数,发现在两个羰基化合物中E模式的非谐性总是较小. 相似文献