Enhancing quantum metrology for multiple frequencies of oscillating magnetic fields by quantum control

Quantum multi-parameter estimation has recently attracted increased attention due to its wide applications, with a primary goal of designing high-precision measurement schemes for unknown parameters. While existing research has predominantly concentrated on time-independent Hamiltonians, little has been known about quantum multi-parameter estimation for time-dependent Hamiltonians due to the complexity of quantum dynamics. This work bridges the gap by investigating the precision limit of multi-parameter quantum estimation for a qubit in an oscillating magnetic field model with multiple unknown frequencies. As the well-known quantum Cramer–Rao bound is generally unattainable due to the potential incompatibility between the optimal measurements for different parameters, we use the most informative bound instead which is always attainable and equivalent to the Holevo bound in the asymptotic limit. Moreover, we apply additional Hamiltonian to the system to engineer the dynamics of the qubit. By utilizing the quasi-Newton method, we explore the optimal schemes to attain the highest precision for the unknown frequencies of the magnetic field, including the simultaneous optimization of initial state preparation, the control Hamiltonian and the final measurement. The results indicate that the optimization can yield much higher precisions for the field frequencies than those without the optimizations. Finally,we study the robustness of the optimal control scheme with respect to the fluctuation of the interested frequencies, and the optimized scheme exhibits superior robustness to the scenario without any optimization.

Quantum metrology with a non-Markovian qubit system

The dynamics of the quantum Fisher information(QFI) of phase parameter estimation in a non-Markovian dissipative qubit system is investigated within the structure of single and double Lorentzian spectra. We use the time-convolutionless method with fourth-order perturbation expansion to obtain the general forms of QFI for the qubit system in terms of a non-Markovian master equation. We find that the phase parameter estimation can be enhanced in our model within both single and double Lorentzian spectra. What is more, the detuning and spectral width are two significant factors affecting the enhancement of parameter-estimation precision.

Contrasting Transport Performance of Electron-and Hole-Doped Epitaxial Graphene for Quantum Resistance Metrology

Epitaxial graphene grown on silicon carbide(Si C/graphene)is a promising solution for achieving a highprecision quantum Hall resistance standard.Previous research mainly focused on the quantum resistance metrology of n-type Si C/graphene,while a comprehensive understanding of the quantum resistance metrology behavior of graphene with different doping types is lacking.Here,we fabricated both n-and p-type Si C/graphene devices via polymer-assisted molecular adsorption and conducted systematic magneto-transport measurements in a wide parameter space of carrier density and temperature.It is demonstrated that n-type devices show greater potential for development of quantum resistance metrology compared with p-type devices,as evidenced by their higher carrier mobility,lower critical magnetic field for entering quantized Hall plateaus,and higher robustness of the quantum Hall effect against thermal degeneration.These discrepancies can be reasonably attributed to the weaker scattering from molecular dopants for n-type devices,which is further supported by the analyses on the quantum interference effect in multiple devices.These results enrich our understanding of the charged impurity on electronic transport performance of graphene and,more importantly,provide a useful reference for future development of graphene-based quantum resistance metrology.

Evaluation of IoT Measurement Solutions from a Metrology Perspective

To professionally plan and manage the development and evolution of the Internet of Things(IoT),researchers have proposed several IoT performance measurement solutions.IoT performance measurement solutions can be very valuable for managing the development and evolution of IoT systems,as they provide insights into performance issues,resource optimization,predictive maintenance,security,reliability,and user experience.However,there are several issues that can impact the accuracy and reliability of IoT performance measurements,including lack of standardization,complexity of IoT systems,scalability,data privacy,and security.While previous studies proposed several IoT measurement solutions in the literature,they did not evaluate any individual one to figure out their respective measurement strengths and weaknesses.This study provides a novel scheme for the evaluation of proposed IoT measurement solutions using a metrology-coverage evaluation based on evaluation theory,metrology principles,and software measurement best practices.This evaluation approach was employed for 12 IoT measure categories and 158 IoT measurement solutions identified in a Systematic Literature Review(SLR)from 2010 to 2021.The metrology coverage of these IoT measurement solutions was analyzed from four perspectives:across IoT categories,within each study,improvement over time,and implications for IoT practitioners and researchers.The criteria in this metrology-coverage evaluation allowed for the identification of strengths and weaknesses in the theoretical and empirical definitions of the proposed IoT measurement solutions.We found that the metrological coverage varies significantly across IoT measurement solution categories and did not show improvement over the 2010–2021 timeframe.Detailed findings can help practitioners understand the limitations of the proposed measurement solutions and choose those with stronger designs.These evaluation results can also be used by researchers to improve current IoT measurement solution designs and suggest new solutions with a stronger metrology base.

Holevo bound independent of weight matrices for estimating two parameters of a qubit

Holevo bound plays an important role in quantum metrology as it sets the ultimate limit for multi-parameter estimations,which can be asymptotically achieved.Except for some trivial cases,the Holevo bound is implicitly defined and formulated with the help of weight matrices.Here we report the first instance of an intrinsic Holevo bound,namely,without any reference to weight matrices,in a nontrivial case.Specifically,we prove that the Holevo bound for estimating two parameters of a qubit is equivalent to the joint constraint imposed by two quantum Cramér–Rao bounds corresponding to symmetric and right logarithmic derivatives.This weightless form of Holevo bound enables us to determine the precise range of independent entries of the mean-square error matrix,i.e.,two variances and one covariance that quantify the precisions of the estimation,as illustrated by different estimation models.Our result sheds some new light on the relations between the Holevo bound and quantum Cramer–Rao bounds.Possible generalizations are discussed.

Physics-informed deep learning for fringe pattern analysis

Recently,deep learning has yielded transformative success across optics and photonics,especially in optical metrology.Deep neural networks (DNNs) with a fully convolutional architecture (e.g.,U-Net and its derivatives) have been widely implemented in an end-to-end manner to accomplish various optical metrology tasks,such as fringe denoising,phase unwrapping,and fringe analysis.However,the task of training a DNN to accurately identify an image-to-image transform from massive input and output data pairs seems at best naive,as the physical laws governing the image formation or other domain expertise pertaining to the measurement have not yet been fully exploited in current deep learning practice.To this end,we introduce a physics-informed deep learning method for fringe pattern analysis (PI-FPA) to overcome this limit by integrating a lightweight DNN with a learning-enhanced Fourier transform profilometry (Le FTP) module.By parameterizing conventional phase retrieval methods,the Le FTP module embeds the prior knowledge in the network structure and the loss function to directly provide reliable phase results for new types of samples,while circumventing the requirement of collecting a large amount of high-quality data in supervised learning methods.Guided by the initial phase from Le FTP,the phase recovery ability of the lightweight DNN is enhanced to further improve the phase accuracy at a low computational cost compared with existing end-to-end networks.Experimental results demonstrate that PI-FPA enables more accurate and computationally efficient single-shot phase retrieval,exhibiting its excellent generalization to various unseen objects during training.The proposed PI-FPA presents that challenging issues in optical metrology can be potentially overcome through the synergy of physics-priors-based traditional tools and data-driven learning approaches,opening new avenues to achieve fast and accurate single-shot 3D imaging.

基于RANSAC算法的2D Metrology在BGA质量检测中的应用研究

针对BGA质量检测中芯片图像的识别定位问题,提出了一种基于RANSAC算法的2D Metrology芯片定位方法。首先进行2D Metrology建模,其次添加对象到2D Metrology模型,然后设置2D Metrology模型参数,应用2D Metrology,最后得到2D Metrology模型的对象定位边结果。该方法基于RANSAC算法,能精确识别模型对象中的边缘轮廓特征,简单易行、定位精度高、鲁棒性好、抗干扰能力强。文中通过实验,与常用的基于最小二乘法的芯片定位方法进行对比,验证了该方法的有效性。

Informative Signal Analysis: Metrology of the Underwater Geomagnetic Singularities in Low-Density Ionic Solution (Sea Water)

The paper tackles the problem of reading singularities of the geomagnetic field in noisy underwater (UW) environments. In particular, we propose a novel metrological approach to measuring low-amplitude geomagnetic signals in hard noisy magnetic environments. This research action was launched to develop a detection system for enforcing the peripheral security of military bases (harbors/coasts and landbases) and for asymmetric warfare. The concept underlying this theory is the spatial stability in the temporal variations of the geomagnetic field in the observation area. The paper presents the development and deployment of a self-informed measurement system, in which the signal acquired from each sensor—observation node—is compared with the signal acquired by the adjacent ones. The effectiveness of this procedure relates to the inter-node (sensor-to-sensor) distance, L;this quantity should, on one hand, correlate the noise and, on the other hand, decorrelate the target signal. The paper presents the results obtained, that demonstrate the ability of self-informed systems to read weak magnetic signals even in the presence of very high noise in low-density ionic solutions (i.e. sea water).

Electrical Metrology Applications of LabVIEW Software

Automation in measurement has wide range of electrical metrology applications and construction of powerful calibration software is one of the highly accurate metrological laboratories’ priorities. Thus, two automatic systems for controlling and calibrating the electrical reference standards have been established at National Institute for Standards (NIS), Egypt. The first system has been built to calibrate the zener diode reference standards while the second one has been built to calibrate the electrical sourcing and measuring instruments. These two systems act as the comprehensive and reliable structure that, from the national electrical standards, disseminates the traceability to all the electrical units under calibration. The software of the two systems has been built using the Laboratory Virtual Instrument Engineering Workbench (LabVIEW) graphical language. The standard development procedures have been followed in the building of both systems software. The software requirement specifications as well as functional specifications are taken into consideration. Design, implementation and testing of the software have been performed. Furthermore, software validation for measurements’ uncertainty as well as results’ compatibility in both automatic and manual modes has been achieved.

Metrology Challenges in 3D NAND Flash Technical Development and Manufacturing

3D NAND technical development and manufacturing face many challenges to scale down their devices,and metrology stands out as much more difficult at each turn.Unlike planar NAND,3D NAND has a three-dimensional vertical structure with high-aspect ratio.Obviously top-down images is not enough for process control,instead inner structure control becomes much more important than before,e.g.channel hole profiles.Besides,multi-layers,special materials and YMTC unique X-Tacking technology also bring other metrology challenges:high wafer bow,stress induced overlay,opaque film measurement.Technical development can adopt some destructive methodology(TEM,etch-back SEM),while manufacturing can only use nondestructive method.These drive some new metrology development,including X-Ray,mass measure and Mid-IR spectroscopy.As 3D NAND suppliers move to>150 layers devices,the existing metrology tools will be pushed to the limits.Still,the metrology must innovate.

Quantum metrology with coherent superposition of two different coded channels

We investigate the advantage of coherent superposition of two different coded channels in quantum metrology.In a continuous variable system,we show that the Heisenberg limit 1/N can be beaten by the coherent superposition without the help of indefinite causal order.And in parameter estimation,we demonstrate that the strategy with the coherent superposition can perform better than the strategy with quantum switch which can generate indefinite causal order.We analytically obtain the general form of estimation precision in terms of the quantum Fisher information and further prove that the nonlinear Hamiltonian can improve the estimation precision and make the measurement uncertainty scale as 1/N^(m) for m≥2.Our results can help to construct a high-precision measurement equipment,which can be applied to the detection of coupling strength and the test of time dilation and the modification of the canonical commutation relation.

Numerical model for evaluating the speckle activity and characteristics of bone tissue under the biospeckle laser system

This paper discusses and studies the composition and characteristics of biospeckle on the surface of bone tissues.We used a laser speckle device to capture biospeckle patterns from fresh pig bone tissue.Traditional speckle activity metrics were used to measure the speckle activity of ex vivo bone tissue over time.Both Gaussian and Lorentzian correlation functions were used to char-acterize the ordered and disordered motion of the bone surface,together with volume scattering,to construct the model.Using the established mathematical model of the spatio-temporal evo-lution of the biospeckle pattern,it is possible to account for the presence of volume scattering from the biospeckle of bones,quantify the ordered or disordered motions in the biological speckle activity at the current time,and assess the ability of laser speckle correlation technique to determine biological activity.

Ultrafast optoelectronic technology for radio metrology applications

Ultrafast optoelectronic technology has been widely used in terahertz time domain spectrum,terahertz imaging technology,terahertz communication and so on,and great progress has been achieved in the past two decade.Recently,this innovative technology has been applied in radio metrology and supplied a potential and hopeful method to solve the existent challenges of calibration devices and equipments with bandwidth up to 100 GHz.This paper generally summarizes the emerging applications of the ultrafast optoelectronic technology in radio metrology.The main applications of this technology in calibrating broadband sampling oscilloscopes,the high-speed photodiodes and calibrating the electrical pulse generators are emphasized,and the testing of monolithic microwave integrated circuits is also presented.

Precision Metrology of Micro Work-pieces on Their Tribological Performance with Error Compensation Method

The frictional properties of micro bearings have strong influence on the performance of the whole system because of tiny scale of micro-electromechanical system (MEMS). To develop micro bearings with low friction,it is important to evaluate the friction behaviors on the micro bearing. The testing system and the principle to evaluate the tribological performance of micromachining work-pieces under the load of mill Newton scale is introduced in paper "A new approach to measure the friction coefficient of micro journal bearings" of Yao et al,. But as the tribological force is faint in micro scale, the measured force is influenced a lot by the testing error. As the equation of that of Yao’s paper is very sensitive to the measured force, the tested result is influenced remarkably by testing error. So it is hard to get precision result. To solve this problem, the test system with new compensation method is introduced to precisely evaluate tribological performance under mill scale. The new metrology method is developed by means of the error compensation from two sets of testing data. The data are the force collected respectively when the friction counterparts rotate in CW(clockwise) and CCW(counter-clockwise) direction. So we deduce the equation of friction coefficient respctively on the condition of journal running in CCW and CW direction. As condition of measuring those two friciton coefficients are alike except the running direction of journal, and then the friction coefficient should be the same because this difference of direction has no influence on the fricition coefficients. Considering this, we unite the both equation, make the data measured in different subtract each other in the equation, and then a new equation can be gotten. This new equation enhances the metrology precision of friction coefficient theoretically thanks to the counteracting of error values in the equation. Using this method we testing the friction of high speed steel journal with hard alloy bearing. The result shows the new compensation method has better precision and repetition than CW and CCW method thanks to the error resistance.

NPPQIC Obtained the Expanded Qualification Recognition by China Metrology Accreditation

Recently the National Petroleum Products Quality Supervision and Inspection Center(NPPQIC)affiliated to the SINOPEC Research Institute of Petroleum Processing(RIPP)has been approved by the China National Certification and Accreditation Administration(CNCA)and has obtained the expanded qualification recognition of China Metrology Accreditation(CMA).

Laser-Driven Light Sources for Nanometrology Applications

Laser-driven light sources(LDLS)have ultrahigh-brightness and broad wavelength range.They are ideal radiation sources for optical metrology tools for advanced process control in semiconductor manufacturing.LDLS sources,with their advantages of 170 nm to 2100 nm wavelength range,have been widely adopted and are being used in volume manufacturing for spectroscopic ellipsometry(SE),spectroscopic scatterometry(SS),and white light interferometry(WLI)applications.Such applications are used to measure critical dimensions(CD),overlay(OVL),and film thickness.

Hamamatsu’s Products for Optical Inspection,Metrology and Monitoring to Improve Yield and Accuracy for Semiconductor Processes

Pursuing small critical dimensions(i.e.14 nm or below)and high integration bring us lots of physical defects causing low yield and functionality failures for foundries.Under this circumstance,inspection,metrology and monitoring technologies are unprecedentedly vital for development of semiconductor industry.Optical and electron beam solutions are the most common two methods in semiconductor manufacturing.Hamamatsu Photonics is now aiming at optical inspection,metrology and monitoring systems market by providing light sources,photodetectors and failure analysis systems for semiconductor equipment manufacturers,foundries and research institutions.In this paper,features and potential applications of light sources,photodetectors(like image sensors,photomultiplier tubes/modules,silicon photomultipliers(modules),(avalanche)photodiodes(arrays)and so on),with the wavelengths ranging from UV to Infrared,are mainly discussed.In addition,Hamamatsu’s star product– failure analysis system to quickly locate faults or defects are introduced.In conclusion,Hamamatsu Photonics is dedicated to develop large varieties of light sources and optical sensors/detector/modules along with failure analysis systems and willing to improve the development of semiconductor and related industries,especially in China.

Novel Pattern-Centric Solution for Xtacking^TM AFM Metrology

3D NAND(three-dimensional NAND type)has rapidly become the standard technology for enterprise flash memories,and is also gaining widespread use in other applications.Continued manufacturing process improvements are essential in delivering memory devices with higher I/O performance,higher bit density,and at lower cost.Current 3D NAND technology involves process steps that form array and peripheral CMOS(Complementary Metal-Oxide-Semiconductor)regions side-by-side,resulting in waste of silicon real estate and film stress compromises,and limits the paths of making advanced 3D NAND devices.An innovative architecture was invented to overcome these challenges by connecting two wafers electrically through metal VIAs(Vertical Interconnect Access)[1].Highly accurate and efficient metrology is required to monitor VIA interface due to increased process complexity and precision requirements.With the advanced processing of AFM(Atomic Force Microscopy)images,highly accurate and precise measurements have been achieved.An inline pattern-centric metrology solution that is designed for high volume mass production of high-performance 3D NAND is presented in this paper.

White Light Interference Solution for Novel 3D NAND VIA Dishing Metrology

In traditional 3D NAND design,peripheral circuit accounts for 20-30%of the chip realestate,which reduces the memory density of flash memory.As 3D NAND technology stacks to 128 layers or higher,peripheral circuits may account for more than 50%of the overall chip area.On the contrast,the Xtacking^TM technology arranges array and logic parts on two different wafers,and connects the memory arrays to the logic circuit by metal VIAs(Vertical Interconnect Accesses)to achieve unprecedented high storage density as well as DRAM level I/O speed.As a consequence,it becomes increasingly significant to monitor metal VIAs depth before wafer bonding process as to ensure reliability of array-logic connections.Currently,AFM(Atom Force Microscopy)is the main stream method of VIA depth monitoring.Apparently,AFM wins the battle of precision,however the low throughput limited its usage in mass production.In order to accomplish the requirement of VLSI production,a WLI(White Light Interference)metrology is revisited and a novel WLI method was developed to monitor VIAs depth.Basically there are two major limitations that keep WLI tools from wider use,transparent film impact and diffraction limitation.In this work,the engineering solutions are illustrated and inline dishing measurement is achieved with high accuracy and precision.

Metrology and Energy Conservation

May 20 is World Metrology Day and the theme of this year is 'Metrology and Energy Conservation.' Energy is not only a vital issue for China, but also for the world. In order to implement Proposal of the CPC Central Committee on the 11th Five-Year Program for National Economic and Social Development, the government bulletin of 5th Plenary Session of the 16th CPC Central Committee announced that 'there shall be marked improvement on resource utilization; the energy consumption for unit GDP shall cut 20%, water consumption of unit industrial added value drop 30%... and the recycle ratio of industrial solid wastes shall raise by 60%.' These are key targets of economic development during the 11th five-year program. To make full use of metrology for energy conservation and energy utilization, the competent metrology department of Chinese Goyernment advanced metrology program in light of China's energy status.……