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71.
由于基频光最后需通过三倍频元件才注入靶室,因此三倍频薄膜元件的抗激光损伤能力,将直接制约系统的能量。三倍频紫外激光薄膜的质量也将是决定系统指标的关键因素之一。在制备紫外增透膜方面,我们在基片和膜堆之间加镀缓冲层,既实现了高透射率,又改善了膜层内的电场强度分布。多次实验表明,样品在小口径元件损伤测量平台上测得的零几率损伤阈值一般大于7/cm^2(355m,10s),折算到3S约4.6/cm^2,折算到1ns为3.13/cm^2。考虑到大光束的破坏结果和小光斑的测量结果不同,我们在星光装置上进行大光束轰击破坏实验。 相似文献
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A new high-T_c (HT_c) rf SQUID working at around 1.3GHz has been developed to avoid electromagnetic interference such as growing mobile communication jamming. This new system works in a frequency range from 1.23 to 1.42GHz (centred at 1.3GHz), which is not occupied by commercial communication. The sensor used in the 1.3GHz rf SQUID is made of a HT_c coplanar superconducting resonator and a large-area HT_c superconducting film concentrator. We have achieved in the 1.3GHz HT_c rf SQUID system a minimal flux noise of 2.5×10^{-5}Φ_0/\sqrt{Hz} and a magnetic field sensitivity of 38fT/\sqrt{Hz} in white noise range, respectively. The effective area of the concentrator fabricated on a 15×15mm^2 substrate is 1.35mm^2. It is shown that the 1.3GHz rf SQUID system has a high field sensitivity. Design and implementation of 1.3GHz HT_c rf SQUID offers a promising direction of rf SQUID development for higher working frequency ranges. 相似文献
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Simulation of dielectric resonator for a high-To radio frequency superconducting quantum interference device
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Nowadays, the high-critical-temperature radio frequency superconducting quantum interference device (high-Tc rf SQUID) is usually coupled to a dielectric resonator that is a standard 10× 10×1 mm^3 SrTiO3 (STO) substrate with a YBa2Cu3O7-δ (YBCO) thin-film flux focuser deposited on it. Recently, we have simulated a dielectric resonator for the high-Tc rf SQUID by using the ANSOFT High Frequency Structure Simulator (ANSOFT HFSS). We simulate the resonant frequency and the quality factor of our dielectric resonator when it is unloaded or matches a 50-Ω impedance. The simulation results are quite close to the practical measurements. Our study shows that ANSOFT HFSS is quite suitable for simulating the dielectric resonator used for the high-Tc rf SQUID. Therefore, we think the ANSOFT HFSS can be very helpful for investigating the characteristics of dielectric resonators for high-Tc rf SQUIDs. 相似文献
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Fabrication and properties of high performance YBa_2Cu_3O_(7-δ) radio frequency SQUIDs with step-edge Josephson junctions
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We describe the fabrication of high performance YBa2Cu3O7-δ(YBCO) radio frequency(RF) superconducting quantum interference devices(SQUIDs), which were prepared on 5 mm×5 mm LaAlO3(LAO) substrates by employing stepedge junctions(SEJs) and in flip-chip configuration with 12 mm×12 mm resonators. The step in the substrate was produced by Ar ion etching with step angles ranging from 47°to 61°, which is steep enough to ensure the formation of grain boundaries(GBs) at the step edges. The YBCO film was deposited using the pulsed laser deposition(PLD) technique with a film thickness half of the height of the substrate step. The inductance of the SQUID washer was designed to be about 157 pH.Under these circumstances, high performance YBCO RF SQUIDs were successfully fabricated with a typical flux-voltage transfer ratio of 83 mV/Φ0, a white flux noise of 29 μΦ0/(Hz)1/2, and the magnetic field sensitivity as high as 80 fT/(Hz)1/2.These devices have been applied in magnetocardiography and geological surveys. 相似文献
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本文对35 GHz和96 GHz电磁波在等离子体中的传输特性进行了理论与实验研究, 得到了电磁波衰减随等离子体密度、碰撞频率和电磁波频率的变化规律. 等离子体密度增加一个数量级时, 电磁波衰减增加一个数量级; 随着等离子体碰撞频率的增加, 电磁波衰减先增加后减小; 随着电磁波频率的增加, 衰减下降. 以激波管为实验平台进行了电磁波在等离子体中传输特性的实验研究, 实验结果和理论结果吻合较好. 理论和实验结果均表明, 提高电磁波频率是解决黑障问题的有效途径. 相似文献