Electron Sagnac gyroscope in an array of mesoscopic quantum rings

The Sagnac effect is an important phase coherent effect in optical and atom interferometers where rotations with respect to an inertial frame are measured in the interference pattern. We analyze the Sagnac effect in a serial array of mesoscopic ring shaped electron interferometers comprised of rings with half-circumferences comparable to the mean free path. The entire array is, however, much larger than the phase coherence length. Phase coherent transport at the level of individual rings leads to a measurable Sagnac effect in the conductance of the chain. We use the signal to noise ratio (SNR) to determine the number of rings needed to measure a desired rotation rate.     

The centennial of the Sagnac experiment in the optical regime: From a tabletop experiment to the variation of the Earth's rotation

The investigation of non-reciprocal behavior of optical beams in a rotating reference frame was the main motivation of the historic tabletop experiment of George Sagnac. His ground-breaking experiment was extended to a very large installation more than a decade later, which was sensitive enough to allow Michelson, Pearson and Gale to resolve the rotation rate of the Earth by an optical interferometer. With the advent of lasers in the early sixties of the last century, rotating laser cavities with a ring structure demonstrated superior performance and very soon matured to a point where mechanical gyroscopes were quickly superseded by laser gyroscopes in aircraft navigation. When vastly upscaled ring lasers were taken back to the laboratory at the end of the 20th century, the goal of applying the Sagnac effect to geodesy for the monitoring of tiny variations of Earth's rotation was the main motivation. The large-ring laser G, which is the most stable instrument out of a series of instruments built by the New Zealand–German collaboration, routinely resolves the rotation rate of the Earth to better than eight orders of magnitude. Since G is directly referenced to the Earth rotation axis, the effect of diurnal polar motion, the Chandler and the Annual wobbles as well as tilts from the solid Earth tides can be found in the interferogram obtained from the ring laser. G has also demonstrated high sensitivity to rotations associated with seismic events. The toroidal eigenmodes of the Earth when they are excited by large earthquakes have been resolved. A surprisingly large amplitude has been measured for Love wave signals contained in the microseismic background signal. This paper summarizes the recent development of highly sensitive large Sagnac gyroscopes, and presents unique results from the measurements of rotations of the earth.     

Chirped area coupled resonator optical waveguide gyroscope

We study the transmission of an optical field through a rotating coupled resonator optical waveguide (CROW) in which the size of the ring resonators changes from one ring to the next. We focus on symmetric integer wavelength chirps of the circumference of the rings relative to the central ring in the array. The transfer matrix method is used to obtain the transmission as a function of the inertial rotation rate Ω resulting from the Sagnac effect. Chirping increases the slope of the oscillations in the transmission as a function of Ω, which can be exploited to further enhance the rotation sensitivity beyond that of a CROW with uniform resonators.     

Generation of surface soliton arrays

We discover that, at the edge of an optical lattice imprinted in a saturable nonlinear medium, one-dimensional surface solitons exist only within a band of light intensities and that they cease to exist when the lattice depth exceeds an upper threshold. We also reveal the generation of arrays of two-dimensional surface solitons mediated by the transverse modulational instability of one-dimensional solitons, a process that is found to exhibit specific features associated to properties of the optical lattice.     

Proposal of a semiconductor ring laser gyroscope

We proposed a novel optical inertial rotation sensor using a semiconductor ring laser (SRL). The frequency difference between the two counter propagating oscillation frequencies was automatically generated in a mechanically rotated SRL, which consisted of a pig-tailed laser diode amplifier module. And the Sagnac frequency shift could be detected at the first time as a beat note by the terminal voltage change of the SRL without branching the circulating optical power. These experimental results verify that an SRL operates as an optical inertial rotation sensor based on the Sagnac effect.     

The Sagnac effect: 20 years of development in matter-wave interferometry

Since the first atom interferometry experiments in 1991, measurements of rotation through the Sagnac effect in open-area atom interferometers have been investigated. These studies have demonstrated very high sensitivity that can compete with state-of-the-art optical Sagnac interferometers. Since the early 2000s, these developments have been motivated by possible applications in inertial guidance and geophysics. Most matter-wave interferometers that have been investigated since then are based on two-photon Raman transitions for the manipulation of atomic wave packets. Results from the two most studied configurations, a space-domain interferometer with atomic beams and a time-domain interferometer with cold atoms, are presented and compared. Finally, the latest generation of cold atom interferometers and their preliminary results are presented.     

集成光学陀螺及相关技术研究的现状与展望

陀螺技术作为惯性导航的重要组成部分已广泛应用于国民经济和军事工业的众多领域.文章综述了包括机械陀螺、光学陀螺和原子陀螺在内的陀螺技术的发展过程和基本特点,着重论述了集成光学陀螺及其相关技术研究的现状与发展趋势.通过对比各种类型陀螺的性能特点,结合导航技术的发展趋势,展望了各种陀螺在相应领域的发展前景.     

集成光学陀螺及相关技术研究的现状与展望

陀螺技术作为惯性导航的重要组成部分已广泛应用于国民经济和军事工业的众多领域.文章综述了包括机械陀螺、光学陀螺和原子陀螺在内的 陀螺技术的发展过程和基本特点,着重论述了集成光学陀螺及其相关技术研究的现状与发展趋势.通过对比各种类型陀螺的性能特点,结合导 航技术的发展趋势,展望了各种陀螺在相应领域的发展前景.     

Improvement of Laser-Beam Irradiation-Intensity Distribution Using Multi Lens Array and Edge-Shaped Plates

A new concept for improving the laser intensity distribution on an inertial confinement fusion target using a phase-controlled multi lens array has been proposed. Circular and hexagonal element lens apertures have been examined, and the circular aperture which eliminated azimuthally asymmetric intensity distribution was chosen. The diffraction fringe of the elementary lens was mitigated in a one-dimensional lens array using edge-shaped plates of a super-Gaussian phase profile. Uniform beam profiles were obtained using a one-dimensional array with 7 spherical lenses and a two-dimensional array with 37 lenses. An approximately flat-top intensity distribution was realized with the lens array with 37 lenses.     

主动相位偏置折叠型萨尼亚克光纤传感阵列时分复用技术

针对折叠结构萨尼亚克(Sagnac)光纤传感阵列存在噪声光与信号光混叠的问题,提出了一种主动相位偏置时分复用方案.在传统梯形结构传感阵列的基础上,通过调整总线光纤的长度关系和附加延迟光纤的方法,使噪声光和信号光依次交替返回而不会发生混叠.进一步分析表明,通过调整延迟光纤环的长度,可以使输入光脉冲的重复频率达到标准时分复用系统重复频率的二分之一.整个阵列的相位偏置由一个与输入光脉冲同步的相位调制信号驱动集成光学芯片实现.实验演示了一个两基元的传感阵列,最小时间间隔为331.25 ns,输入光脉冲重复频率可达754.727 kHz,在5 kHz处相位灵敏度为7.3μrad√(Hz),探头间串扰约为-51.75 dB.     

Ultra-compact two-dimensional plasmonic nano-ring antenna array for sensing applications

In this paper, a novel optical nanoantenna based on two-dimensional plasmonic nano-ring antenna array is proposed, investigated numerically and compared with a nano-disk antenna array. The results show that the nano-ring structure has resonances similar to the resonances of nano-disk structure but in higher wavelengths. These resonances are tunable by varying the structural parameters of the ring. The optical properties of the proposed structure are investigated in the context of designing a plasmonic refractive index sensor. The nano-ring antenna array sensor has large sensitivity in comparison to the conventional nano-disk antenna arrays. The special feature of the presented structure and the device concepts introduced in this work are applicable in realization of various integrated components and could play an important role in development of plasmonic sensors.     

Anderson cross-localization

We report Anderson localization in two-dimensional optical waveguide arrays with disorder in waveguide separation introduced along one axis of the array, in an uncorrelated fashion for each waveguide row. We show that the anisotropic nature of such disorder induces a strong localization along both array axes. The degree of localization in the cross-axis remains weaker than that in the direction in which disorder is introduced. This effect is illustrated both theoretically and experimentally.     

Sagnac effect in coupled-resonator slow-light waveguide structures

We study the effect of rotation on the propagation of electromagnetic waves in slow-light waveguide structures consisting of coupled microring resonators. We show that such configurations exhibit a new type of Sagnac effect which can be used for the realization of highly compact integrated rotation sensors and gyroscopes.     

High Sensitivity Ring Resonator Gyroscopes

Abstract

A recent study discussing different ring-resonator- and fiber-based gyroscopes concluded that the performance of a single-loop resonant fiber-optical gyro exceeds that of more complex ring-resonator-based gyros. It is demonstrated here that this conclusion applies as well to a gyro that consists of a closed loop of coupled-ring resonators with internal feedback. While this device is more sensitive to rotation than other gyro structures with the same footprint and losses, a simpler alternative consisting of a resonant single ring with an area equal to complex gyro structures still displays a higher degree of sensitivity.     

二维圆周光综合孔径阵的优化排列及其成像特性研究

光综合孔径成像的原理是应用干涉原理在空间频率域中进行采样,并通过傅里叶反变换或其他数值变换方法得到空间分辨力远高于单个孔径成像系统的目标图像。由若干个相同的小孔径在二维圆周上优化排列组成的综合孔径成像系统可以在二维空间频率域中实现较为均匀分布的、具有无冗余度的采样点覆盖,为高质量实时成像提供了一个有效的途径。运用模拟退火算法对由7～16个子孔径组成的二维圆周综合孔径阵列进行优化排列。并依据光学衍射成像原理,从空域和频域两个方面详细分析了二维圆周上优化排列与均匀排列光综合孔径阵的成像特性。对7～16个子孔径组成的光综合孔径的仿真结果表明：无论是在空域还是频域上,子孔径直径增大、孔径数目增多以及综合孔径阵的优化排列都是有利于提高成像质量的。但综合后的子孔径的直径的增大,虽然能获得极高的角分辨力,却并不利于成像质量的提高。     

新颖的微流控电调谐空间光开关

提出了一种微流控电调谐非机械空间光开关器件,该器件的基本形式为“光输入阵列+光交换空间+光输出阵列”的结构,采用“水/油/水”液体棱镜作为偏光控制单元.在特定电压范围（30~110 V）内,通过电润湿效应作用的液体棱镜光束偏转角可在约－15°~15°之间连续可调.由此可构造多种平面甚至立体光开关阵列.     

Imaging Properties of Planar Microlens Arrays

The planar microlens arrays is a two-dimensional array of optical component which is fabricated monolithically available. Imaging properties of planar microlens arrays are described, which provide both image multiplexer and erect, unit magnification images.     

Performance comparison of slow‐light coupled‐resonator optical gyroscopes

We investigate the connection between group velocity and rotation sensitivity in a number of resonant gyroscope designs. Two key comparisons are made. First, we compare two conventional sensors, namely a resonant fiber optic gyroscope (RFOG) and an interferometric fiber optic gyroscope (FOG). Second, we compare the RFOG to several recently proposed coupled‐resonator optical waveguide (CROW) gyroscopes. We show that the relationship between loss and maximum rotation sensitivity is the same for both conventional and CROW gyroscopes. Thus, coupling multiple resonators together cannot enhance rotation sensitivity. While CROW gyroscopes offer the potential for large group indices, this increase of group index does not provide a corresponding increase in the maximum sensitivity to rotation. For a given footprint and a given total loss, the highest sensitivity is shown to be achieved either in a conventional RFOG utilizing a single resonator, or a conventional FOG.     

同时测量扭转角度和扭转方向的侧漏光子晶体光纤扭转传感器

基于所研制的侧漏型光子晶体光纤,提出并构建了出一种同时检测扭转角度 和扭转方向的高灵敏度Sagnac干涉仪型光纤扭转传感器.顺时针扭转时, 传感器传输谱向短波长方向偏移;逆时针扭转,向长波长方向偏移. 对传感器扭转特性的实验研究结果表明,构成Sagnac干涉仪的侧漏型光子晶体光纤的长度, 对扭转敏感系数和扭转角度测量范围起着决定性作用.当光纤长度较短时, 扭转传感器具有较大的扭转灵敏度,但扭转角度测量范围较小;光纤长度增加时,扭转灵敏度减小, 扭转角度测量范围增大.当构成Sagnac干涉仪的侧漏型光子晶体光纤长度为14.85 cm时, 传感器的扭转敏感系数可达到0.9354 nm/(°),扭转角度测量范围为-90°—90°; 光纤长度为32 cm时,最大扭转敏感系数降为0.2132 nm/(°), 扭转角度测量范围扩展至-180°—180°. 采用二维测量矩阵法可以有效排除温度对扭转角度的测量的影响. 关键词： 光纤传感器 侧漏型光子晶体光纤 扭转传感器 Sagnac干涉仪