Author Affiliations
Abstract
1 Interdisciplinary Center for Quantum Information, State Key Laboratory of Modern Optical Instrumentation, ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 310027, China
2 International Joint Innovation Center, Key Laboratory of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang, The Electromagnetics Academy at Zhejiang University, Zhejiang University, Haining 314400, China
3 Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
4 Centre for Disruptive Photonic Technologies, The Photonics Institute, Nanyang Technological University, Singapore 639798, Singapore
5 e-mail: yangyihao@zju.edu.cn
6 e-mail: blzhang@ntu.edu.sg
7 e-mail: hansomchen@zju.edu.cn
The in-plane negative refraction of high-momentum (i.e., high-) photonic modes could enable many applications such as imaging, focusing, and waveguiding in a planar platform at deep-subwavelength scales. However, its practical implementation in experiments remains elusive so far. Here we propose a class of hyperbolic metasurfaces, which is characterized by an anisotropic magnetic sheet conductivity and can support the in-plane ultra-high- magnetic designer polaritons. Based on such metasurfaces, we report the experimental observation of the all-angle negative refraction of designer polaritons at extremely deep-subwavelength scales. Moreover, we directly visualize the designer polaritons with hyperbolic dispersions. Importantly, for these hyperbolic polaritons, we find that their squeezing factor is ultra-large. To be specific, it can be up to 129 in the experiments, an ultra-high value exceeding those in naturally hyperbolic materials. This work may pave a way toward exploring the extremely high confinement and unusual propagation of magnetic designer polaritons over monolayer or twisted bilayer hyperbolic metasurfaces.
Photonics Research
2021, 9(8): 08001540
1 中国科学技术大学环境科学与光电技术学院, 安徽 合肥 230031
2 中国科学院安徽光学精密机械研究所, 安徽 合肥 230031
离轴积分腔输出光谱技术是痕量气体检测的重要方法, 这种测量方法的检测限容易受到残余腔模式噪声和背景噪声的影响。 通过注入射频白噪声到激光器的调制电流中, 以减小离轴积分腔输出光谱中的残余腔模式噪声, 同时利用波长调制技术抑制了背景信号的影响, 进一步提高了基于离轴积分腔输出光谱技术的甲烷传感系统的信噪比。 首先, 详细研究了不同功率射频白噪声对空气中甲烷吸收光谱的影响, 并对吸收谱的线宽进行了分析, 计算出了不同功率噪声扰动下的吸收谱对应的最佳调制幅度。 随后, 研究了不同功率的射频白噪声对2f信号的影响。 结果表明, 随着扰动噪声功率的增加, 基线噪声水平和2f信号幅值同时减小。 对几组2f信号的信噪比进行分析, 确定了射频白噪声提高系统信噪比的最佳功率为-25 dBm。 最后, 研究了0.05~2.2×10-6浓度范围内, 甲烷浓度与2f信号之间的对应关系, 结果表明: 在甲烷浓度小于1.0×10-6时, 甲烷浓度与2f信号之间的线性度为0.999 6; 在甲烷浓度为0.1~2.2×10-6时, 甲烷浓度与2f信号之间呈曲线关系, 二阶多项式拟合的相关度为0.999 89。 此外, 对浓度为2.2×10-6的甲烷气体进行了长时间的测量, 并利用Allan方差对系统的稳定性进行了分析, 分析结果表明系统的最佳积分时间为1 250 s, 系统的可探测极限约为1.2×10-9。 最后, 使用建立的甲烷气体探测系统, 对大气环境中的甲烷气体浓度进行了长达两个昼夜的检测, 结果显示甲烷浓度的昼夜变化规律是昼降夜升, 浓度昼夜波动范围在2.02~2.3×10-6范围内, 平均浓度为2.14×10-6。 本研究为离轴积分腔输出光谱技术在痕量气体测量方面的应用提供了一定的参考, 对高精密的原位痕量气体测量仪器的研发具有重要的指导价值。
离轴积分腔输出光谱 波长调制 射频白噪声 腔模噪声 检测极限 Off-axis integrated cavity output spectroscopy Wavelength modulation RF white noise Cavity mode noise Detection limit 光谱学与光谱分析
2020, 40(9): 2657
为了测量散斑干涉条纹,从而计算出被测物体的微位移,提出了一种基于AT89S52芯片的解决方案。运用单片机驱动步进电机,精准控制光敏传感器的移动,利用传感器判定暗条纹中心,结合软件进行实时处理,获得再现干涉条纹间距。实验结果表明,该设计方案对散斑位移的测量精度可达0.001 mm。
微位移测量 相干光学 单片微型计算机 步进电机 光敏传感器 micro-displacement measurement coherence optics microcontroller unit step motor light sensor
Author Affiliations
Abstract
Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201820, China
A high-speed 8-channel fiber Bragg grating (FBG) sensing system is designed to monitor safety of modern ships and applied to measure strain distribution of large thruster structure with 335-Hz maximum natural frequency. All the monitoring points are tested synchronously, and the data acquisition frequency is 1 000 Hz. The strain resolution of the system is 1 με with the measurement range of ±3 300 με. Results from the tests onshore and at sea are discussed together to accomplish prediction of the dynamic data. The max stress of the whole structure is more than 40 MPa. Experimental results are accordant with mechanical theories.
060.2370 Fiber optics sensors 230.1480 Bragg reflectors 220.4840 Testing Collection Of theses on high power laser and plasma physics
2012, 10(1): S20604
Author Affiliations
Abstract
Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201820, China
A high-speed 8-channel fiber Bragg grating (FBG) sensing system is designed to monitor safety of modern ships and applied to measure strain distribution of large thruster structure with 335-Hz maximum natural frequency. All the monitoring points are tested synchronously, and the data acquisition frequency is 1 000 Hz. The strain resolution of the system is 1 με with the measurement range of ±3 300 με. Results from the tests onshore and at sea are discussed together to accomplish prediction of the dynamic data. The max stress of the whole structure is more than 40 MPa. Experimental results are accordant with mechanical theories.
060.2370 Fiber optics sensors 230.1480 Bragg reflectors 220.4840 Testing Chinese Optics Letters
2012, 10(s2): S20604
Author Affiliations
Abstract
中国科学院上海光学精密机械研究所高功率激光物理联合实验室, 上海 201800
The technique of Brillouin scattering distributed optical fiber sensing has been presented. Optical heterodyne detection was used to detect the weak Brillouin back scattering signal based on single longitudinal mode distributed feedback (DFB) laser and electric optical modulation technique. The scattering signal was amplified effectively by improving the filter and erbium doped fiber amplifier (EDFA). The 11 GHz radio-frequency (RF) signal of Brillouin back scattering is gathered and averaged. The experimental procedures and results are presented. The results show that the peak power of Brillouin back scattering at 11 GHz can reach 50 mV, and the intensity noise of light source induced the system's signal to noise ratio (SNR) decreased greatly, which reduced the difficulty of signal process in demodulation system. The experimental results confirm that the configuration is feasible.
测量与计量 光纤传感器 布里渊散射 电光调制 相干检测 measurement and metrology optical fiber sensors Brillouin scattering electro-optical modulation optical coherent detection Collection Of theses on high power laser and plasma physics
2007, 5(1): 233
Author Affiliations
Abstract
中国科学院上海光学精密机械研究所高功率激光物理联合实验室, 上海 201800
Based on the rate equation, the amplification performance of small-mode-area (SMA) and large-mode-area (LMA) ytterbium-doped double-clad fiber amplifiers was studied using the finite-difference method. The Yb-doped double-clad fibers with the mode diameter 6.5 μm and 20 μm were used as the gain media for the amplification of narrow-band signals. Under the pump laser at the center wavelength of 915 nm, the relationships between output power and input signal power, pump power as well as fiber length, were discussed for SMA and LMA. Especially for LMA fiber amplifiers, it is important to choose the optimal fiber length. For the fiber amplifier with different mode diameters, the optimal pump power and fiber length were also analyzed. It is obtained that the critical pump power is about 4 W with the fiber length of 4 m, which is in accord with the experimental results. The results provide a theoretical guide to optimize fiber type and fiber length considering available signal and pump power, desired gain and mode requirement of fiber amplifiers.
激光技术 双包层光纤放大器 数值模拟 大模场面积 小模场面积 laser technique double-clad fiber amplifier numerical simulation large-mode-area small-mode-area Collection Of theses on high power laser and plasma physics
2007, 5(1): 192
Author Affiliations
Abstract
Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800
By solving a set of time-dependent equations, the characteristics of the ytterbium-doped double-clad fiber amplifier are presented. Besides the steady state in the fiber of the upper-state population, pump power and amplified spontaneous emission without the input signal, the dynamic characteristics of the high power Gaussian pulse amplification like the evolution of pulse waveform distortion, upper-state population distribution and stored energy and pulse energy of the amplifier under the forward and backward pump, are simulated. The relations between the output pulse energy of the amplifier and the different input pulse peak power or pump power are also discussed. The models and results can provide important guide for the design and optimization of the high power pulse amplification.
光纤放大 数值模拟 双包层 脉冲放大 060.2320 060.2430 Collection Of theses on high power laser and plasma physics
2007, 5(1): 188
Author Affiliations
Abstract
Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800
A diode-pumped Yb-doped double-clad fiber amplifier (YDDCFA) with the narrow bandwidth continuous wave (CW) and pulse input signal is investigated. The input single-mode (SM) signal bandwidth is 10^(-4) nm from a distributed feedback (DFB) fiber laser. The saturated gain of the CW amplification is 11 dB at the forward pump. And besides CW signals, we also amplify pulses with duration of 150 ns and the 1-Hz repetition. The pulse is amplified to 2 W of peak power, 0.31 microjoule of energy, 23 dB of gain and less than 6% of stability at the forward pump power of 1.4 W. For higher power, reflections and backscattering can generate the self pulsation in the amplifier. The results are important for the development of the narrow-band double-clad fiber amplifier.
060.2320 060.2430 Collection Of theses on high power laser and plasma physics
2007, 5(1): 185
