Polarization,a fundamental behavior of electromagnetic waves,holds immense potential across diverse domains such as environmental monitoring,biomedicine,and ocean exploration.However,achieving efcient modulation of te...Polarization,a fundamental behavior of electromagnetic waves,holds immense potential across diverse domains such as environmental monitoring,biomedicine,and ocean exploration.However,achieving efcient modulation of terahertz waves with wide operational bandwidth poses signifcant challenges.Here,we introduce an all-silicon polarization converter designed specifcally to operate in the terahertz range of the electromagnetic spectrum.Simulation results demonstrate that the average conversion efciency of cross-linear waves exceeds 80%across a wide frequency range spanning from 1.00 to 2.32 THz,with the highest conversion efciency peaking at an impressive 99.97%.Additionally,our proposed structure facilitates linear-to-circular polarization conversion with an ellipticity of 1 at 0.85 THz.Furthermore,by rotating the crossshaped microstructure,active control over arbitrary polarization states can be achieved.To summarize,the proposed structure ofers remarkable fexibility and ease of integration,providing a reliable and practical solution for achieving broadband and efcient polarization conversion of terahertz waves.展开更多
We propose and experimentally demonstrate a high quality(Q)-factor all-silicon bound state in the continuum(BIC)metasurface with an imperforated air-hole array.The metasurface supports two polarization-insensitive BIC...We propose and experimentally demonstrate a high quality(Q)-factor all-silicon bound state in the continuum(BIC)metasurface with an imperforated air-hole array.The metasurface supports two polarization-insensitive BICs originated from guided mode resonances(GMRs)in the frequency range of 0.4 to 0.6 THz,and the measured Q-factors of the two GMRs are as high as 334 and 152,respectively.In addition,the influence of the thickness of the silicon substrate on the two resonances is analyzed in detail.The proposed all-silicon THz metasurface has great potential in the design and application of high-Q metasurfaces.展开更多
In silicon photonics, the carrier depletion scheme has been the most commonly used mechanism for demonstrating high-speed electro-optic modulation. However, in terms of phase modulation efficiency, carrieraccumulation...In silicon photonics, the carrier depletion scheme has been the most commonly used mechanism for demonstrating high-speed electro-optic modulation. However, in terms of phase modulation efficiency, carrieraccumulation-based devices potentially offer almost an order of magnitude improvement over those based on carrier depletion. Previously reported accumulation modulator designs only considered vertical metal-oxidesemiconductor(MOS) capacitors, which imposes serious restrictions on the design flexibility and integratability with other photonic components. In this work, for the first time to our knowledge, we report experimental demonstration of an all-silicon accumulation phase modulator based on a lateral MOS capacitor. Using a Mach–Zehnder interferometer modulator with a 500-μm-long phase shifter, we demonstrate high-speed modulation up to 25 Gbit∕s with a modulation efficiency(V_πL_π) of 1.53 V·cm.展开更多
研究全硅基光学二极管,即在硅基芯片上实现非互易光学传输,是一项具有广泛应用前景并极具技术挑战的研究课题。采用硅基谐振结构微纳器件中非线性光学效应,完成光学非互易传输,是当前实现硅基光学二极管的重要方法。结合硅基波导中的非...研究全硅基光学二极管,即在硅基芯片上实现非互易光学传输,是一项具有广泛应用前景并极具技术挑战的研究课题。采用硅基谐振结构微纳器件中非线性光学效应,完成光学非互易传输,是当前实现硅基光学二极管的重要方法。结合硅基波导中的非线性光学效应的基本原理,以及谐振结构微纳器件的基本模型,分析了硅基谐振结构微纳器件构成的光学二极管中的非互易传输问题。仿真结果表明,依靠谐振结构中的非线性光学效应产生的器件非互易特性仅存在于特定频率,这种非互易性在谐振波长附近的一段频率区域较为明显,考虑3 d B以上的非互易传输比率区间,区间宽度累计可以达到10.6 GHz以上。分析了微环耦合系数对硅基光学二极管的非互易传输比率的影响,得出结论:精确控制波导的耦合系数,使得微环工作在接近临界耦合的状态,有助于提升器件的非互易传输比率。展开更多
基于激光切片原理的分析,给出了厚硅片的高速激光切片方法,采用平凸腔补偿工作物质的热透镜效应,利用Nd∶YAG棒本身的自孔径选模作用,获得了光束质量因子M2等于4.19的50 W 1.064μm激光输出。选取合适的扩束倍数、重复频率和出气孔直径...基于激光切片原理的分析,给出了厚硅片的高速激光切片方法,采用平凸腔补偿工作物质的热透镜效应,利用Nd∶YAG棒本身的自孔径选模作用,获得了光束质量因子M2等于4.19的50 W 1.064μm激光输出。选取合适的扩束倍数、重复频率和出气孔直径,当切割0.75 mm厚的硅片时,切片速度达400 mm/min;当切割两层叠放的0.75 mm厚的硅片时,切片速度达到100 mm/min。切片的切口光滑,切缝较窄,重复精度高,切片质量好,达到用传统方法难以达到的切片效果。展开更多
目的:比较使用口内扫描法和传统硅橡胶法制取种植磨牙单冠的临床修复效果评价。方法:选择62例患者(共86颗后牙),随机分为试验组和对照组,每组43颗牙(其中前磨牙13颗,磨牙30颗)。临床分别采用硅橡胶法和口内扫描法制取印模,制作氧化锆全...目的:比较使用口内扫描法和传统硅橡胶法制取种植磨牙单冠的临床修复效果评价。方法:选择62例患者(共86颗后牙),随机分为试验组和对照组,每组43颗牙(其中前磨牙13颗,磨牙30颗)。临床分别采用硅橡胶法和口内扫描法制取印模,制作氧化锆全瓷修复体,于治疗后2周复诊,采用VAS评分量表及改良的美国公共卫生总署(United states public health service,USPHS)评价系统对修复效果及舒适度进行评价。结果:口内扫描法组的患者满意度更高,舒适度更好,两组USPHS评分中除口内扫描组修复体的边缘适合性A级比例比对照组高外,其余指标的A级比例差异无统计学意义(P>0.05)。结论:口内扫描技术应用在种植磨牙单冠的印模制作中,修复效果良好、精度高外,患者满意度高,值得临床推广应用。展开更多
基金fnancial support from the National Key Research and Development Program of China(No.2022YFA1203502)the National Natural Science Foundation of China(Grant No.U2230114).
文摘Polarization,a fundamental behavior of electromagnetic waves,holds immense potential across diverse domains such as environmental monitoring,biomedicine,and ocean exploration.However,achieving efcient modulation of terahertz waves with wide operational bandwidth poses signifcant challenges.Here,we introduce an all-silicon polarization converter designed specifcally to operate in the terahertz range of the electromagnetic spectrum.Simulation results demonstrate that the average conversion efciency of cross-linear waves exceeds 80%across a wide frequency range spanning from 1.00 to 2.32 THz,with the highest conversion efciency peaking at an impressive 99.97%.Additionally,our proposed structure facilitates linear-to-circular polarization conversion with an ellipticity of 1 at 0.85 THz.Furthermore,by rotating the crossshaped microstructure,active control over arbitrary polarization states can be achieved.To summarize,the proposed structure ofers remarkable fexibility and ease of integration,providing a reliable and practical solution for achieving broadband and efcient polarization conversion of terahertz waves.
基金supported by the National Natural Science Foundation of China(Nos.61875179,12004362,and 62175224)。
文摘We propose and experimentally demonstrate a high quality(Q)-factor all-silicon bound state in the continuum(BIC)metasurface with an imperforated air-hole array.The metasurface supports two polarization-insensitive BICs originated from guided mode resonances(GMRs)in the frequency range of 0.4 to 0.6 THz,and the measured Q-factors of the two GMRs are as high as 334 and 152,respectively.In addition,the influence of the thickness of the silicon substrate on the two resonances is analyzed in detail.The proposed all-silicon THz metasurface has great potential in the design and application of high-Q metasurfaces.
基金Engineering and Physical Sciences Research Council(EPSRC)(EP/M008975/1,EP/M009416/1,EP/N013247/1,EP/R003076/1)EU Seventh Framework Programme(FP7)Marie-Curie Carrier-Integration-Grant(PCIG13-GA-2013-618116)
文摘In silicon photonics, the carrier depletion scheme has been the most commonly used mechanism for demonstrating high-speed electro-optic modulation. However, in terms of phase modulation efficiency, carrieraccumulation-based devices potentially offer almost an order of magnitude improvement over those based on carrier depletion. Previously reported accumulation modulator designs only considered vertical metal-oxidesemiconductor(MOS) capacitors, which imposes serious restrictions on the design flexibility and integratability with other photonic components. In this work, for the first time to our knowledge, we report experimental demonstration of an all-silicon accumulation phase modulator based on a lateral MOS capacitor. Using a Mach–Zehnder interferometer modulator with a 500-μm-long phase shifter, we demonstrate high-speed modulation up to 25 Gbit∕s with a modulation efficiency(V_πL_π) of 1.53 V·cm.
文摘研究全硅基光学二极管,即在硅基芯片上实现非互易光学传输,是一项具有广泛应用前景并极具技术挑战的研究课题。采用硅基谐振结构微纳器件中非线性光学效应,完成光学非互易传输,是当前实现硅基光学二极管的重要方法。结合硅基波导中的非线性光学效应的基本原理,以及谐振结构微纳器件的基本模型,分析了硅基谐振结构微纳器件构成的光学二极管中的非互易传输问题。仿真结果表明,依靠谐振结构中的非线性光学效应产生的器件非互易特性仅存在于特定频率,这种非互易性在谐振波长附近的一段频率区域较为明显,考虑3 d B以上的非互易传输比率区间,区间宽度累计可以达到10.6 GHz以上。分析了微环耦合系数对硅基光学二极管的非互易传输比率的影响,得出结论:精确控制波导的耦合系数,使得微环工作在接近临界耦合的状态,有助于提升器件的非互易传输比率。
文摘目的:比较使用口内扫描法和传统硅橡胶法制取种植磨牙单冠的临床修复效果评价。方法:选择62例患者(共86颗后牙),随机分为试验组和对照组,每组43颗牙(其中前磨牙13颗,磨牙30颗)。临床分别采用硅橡胶法和口内扫描法制取印模,制作氧化锆全瓷修复体,于治疗后2周复诊,采用VAS评分量表及改良的美国公共卫生总署(United states public health service,USPHS)评价系统对修复效果及舒适度进行评价。结果:口内扫描法组的患者满意度更高,舒适度更好,两组USPHS评分中除口内扫描组修复体的边缘适合性A级比例比对照组高外,其余指标的A级比例差异无统计学意义(P>0.05)。结论:口内扫描技术应用在种植磨牙单冠的印模制作中,修复效果良好、精度高外,患者满意度高,值得临床推广应用。
