- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Wavefront Aberration of Spheres With Local Deviations and Their Influence on the Radius Value
摘要： The spherical interferometer was one of the key experiments for the determination of the Planck constant through the X-ray crystal density method and will be essential for the realization of the kilogram on the basis of the new definition. This experiment affords the volume value and currently reached a relative uncertainty of 7·10^{-9}. Therefore, an optical simulation of the experimental setup was initiated and could reduce the erstwhile dominating the influence of the wavefront. The first results of spheres with low form aberration in the order of 50 nm were published. For the transfer of spheres with higher deviation from roundness, the impact of the form aberration on the volume value was investigated. Synthetic data of spheres with local deviations as well as measured data of spheres with more complex topography were simulated and evaluated in detail. A magnification of these particular deviations leads to a better comprehension of the dependence of the topography to the wavefront aberration.
关键词： simulation,metrology,measurement uncertainty,Interferometry,uncertainty
更新于2025-09-19 17:15:36
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Dynamic Mach–Zehnder interferometer based on a Michelson configuration and a cube beam splitter system
摘要： We developed simultaneous phase-shifting system based on a Mach–Zehnder interferometer and a replicating system integrated by a Michelson configuration and a cube beam splitter. The system is capable to obtain four simultaneous interferograms in a single capture, and the phase shifts are controlled by placing a linear polarizer in each replica obtained. The system retrieves four interferograms with a relative phase shift of π/2 and the optical phase map is calculated using the four-step algorithm. In addition, the configuration presents potential capabilities for generating spiral interference patterns. To show the advantage of the technique, experimental results are presented for static and dynamic samples.
关键词： Phase shift,Interferometry,Optical metrology
更新于2025-09-19 17:15:36
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - A Novel Approach to Amine-Thiol Molecular Precursors for Fabrication of High Efficiency Thin Film CISSe/CIGSSe Devices
摘要： 3-D coordinate transformation, which is based on aligning two sets of common reference points, is frequently applied in large-scale combined measurement to unify coordinate frames and tie individual measurement systems together. However, it introduces uncertainty into the ?nal measurement results. This uncertainty must be quanti?ed to make the results complete. This paper presents a novel approach to the uncertainty analysis of 3-D coordinate transformation based on the weighted total least squares adjustment. This approach takes full account of the uncertainty characteristics of measuring instruments and is simple in calculation. In this approach, the transformation uncertainty of a point in a world frame is analyzed carefully. The simulations show that the transformation uncertainty has a distribution of concentric ellipsoids and is affected by the measurement uncertainties and layout of common points. Besides, strategies for minimizing transformation uncertainty are recommended. The experimental results from a laser tracker prove that this proposed approach is valid under normal instrument operating conditions and that these strategies are feasible and ef?cient.
关键词： Coordinate transformation,error analysis,uncertainty,large-scale metrology,position measurement,sensor fusion
更新于2025-09-19 17:13:59
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The Vibration Behavior of Suba??Micrometer Gas Vesicles in Response to Acoustic Excitation Determined via Laser Doppler Vibrometry
摘要： The ability to monitor sub-micrometer gas vesicles’ (GVs) vibration behavior to nonlinear buckling and collapse using laser Doppler vibrometry is reported, providing a precise noncontact technique for monitoring the motion of sub-micrometer objects. The fundamental and first harmonic resonance frequencies of the vesicles are found to be 1.024 and 1.710 GHz, respectively. An interparticle resonance is furthermore identified at ≈300 MHz, inversely dependent upon the agglomerated GV size of around 615 nm. Most importantly, the vesicles amplify and broaden input acoustic signals at far lower frequencies—for example, 7 MHz—associated with medical and industrial applications, and they are found to transition from a linear to nonlinear response at 150 kPa and to collapse at 350 kPa or greater.
关键词： bubble dynamics,gas vesicles,sub-micrometer object metrology,acoustofluidics,laser Doppler vibrometry
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - The Luminescent Down Shifting Effect of Single-Junction GaAs Solar Cell with Perovskite Quantum Dots
摘要： We present a method for quantifying a risk for killer defects at layer level and estimating yield for substrate packages using information from design ?les. To calculate risk ranks and predicted yield, we de?ne a risk distance that is a key parameter extracted from designs using image processing techniques. In order to validate our model, we analyze two different designs, each having multiple layers, and compare with data from baseline lots. It is shown that there is an inverse correlation between risk layer ranks and yield. Estimated yield based on our model is compared with baseline yield for four layers of the second design. The model-to-baseline yield difference is less than 1% for three layers we tested.
关键词： metrology sampling,circuit analysis,assembly,yield estimation,integrated circuit packaging,Yield prediction
更新于2025-09-19 17:13:59
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Characterization and applications of auto-locked vacuum-sealed diode lasers for precision metrology
摘要： We demonstrate the performance characteristics of a new class of vacuum-sealed, autolocking diode laser systems and their applications to precision metrology. The laser is based on adaptations of a design that uses optical feedback from an interference filter and it includes a vacuum-sealed cavity, an interchangeable base-plate, and an autolocking digital controller. A change of the base-plate allows operation at desired wavelengths in the visible and near infrared spectral range, whereas the autolocking ability allows the laser to be tuned and frequency stabilized with respect to atomic, molecular, and solid-state resonances without human intervention using a variety of control algorithms programmed into the same controller. We characterize the frequency stability of this laser system based on the Allan deviation (ADEV) of the beat note and of the lock signal. We find that the ADEV floor of 2 × 10?12 and short-term linewidth of ～200 kHz are strongly influenced by current noise and vacuum sealing. Reducing the current noise and cavity pressure decreases the ADEV floor and increases the averaging time at which the floor occurs, which is a signature of long-term stability. We also show that evacuating the cavity to ～1 Torr reduces the range of the correction signal of the feedback loop by approximately one order of magnitude, thereby increasing the lock range of the controller. The long-term stability allows the laser to be incorporated into a commercial gravimeter for accurate measurements of gravitational acceleration at the level of a few parts-per-billion, which are comparable to values obtained with an iodine-stabilized He–Ne laser. The autolocking and pattern-matching features of the controller allow the laser to be tuned and stabilized with respect to a temperature tunable transmission spectrum of a fiber-Bragg grating. This capability may be suitable for the development of a differential absorption LIDAR transmitter that can generate data at both on-line and off-line lock points using a single laser.
关键词： precision metrology,autolocking,frequency stability,LIDAR,vacuum-sealed,diode laser,gravimeter
更新于2025-09-19 17:13:59
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A new large-scale posture measurement system based on a six-laser tracer multilateral method
摘要： To realize high-accuracy posture measurement in large scale, a posture measurement system is proposed in this study based on a six-laser multilateral method, mainly composed of six laser tracers and three reflectors—a different number of laser tracers tracks each mirror. But in this state, the system is positive definite, and it cannot achieve the system parameters by self-calibration. To solve this problem, a stepwise calibration method to obtain the system parameters by three-step calibration is presented. Simulations and experiments are carried out to verify the effectiveness of the proposed method. The experimental results show that the posture errors are distributed over [?13.6″, 6.6″] when the measurement range is [5 m, 7 m], which shows that the new measurement system has a high posture measurement accuracy in large scale.
关键词： laser multilateral method,stepwise calibration,large scale,posture measurement,metrology
更新于2025-09-19 17:13:59
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Phononic-waveguide-assisted steady-state entanglement of silicon-vacancy centers
摘要： Multiparticle entanglement is of great significance for quantum metrology and quantum information processing. We present here an efficient scheme for generating stable multiparticle entanglement in a solid-state setup, where an array of silicon-vacancy centers are embedded in a quasi-one-dimensional acoustic diamond waveguide. In this scheme, the continuum of phonon modes induces a controllable dissipative coupling among the SiV centers. We show that, by an appropriate choice of the distance between the SiV centers, the dipole-dipole interactions can be switched off due to destructive interference, thus realizing a Dicke superradiance model. This gives rise to an entangled steady state of SiV centers with high fidelities. The protocol provides a feasible setup for the generation of multiparticle entanglement in a solid-state system.
关键词： Multiparticle entanglement,quantum information processing,acoustic diamond waveguide,quantum metrology,silicon-vacancy centers,Dicke superradiance model
更新于2025-09-19 17:13:59
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[IEEE 2019 Joint Conference of the IEEE International Frequency Control Symposium anEuropean Frequency and Time Forum (EFTF/IFC) - Orlando, FL, USA (2019.4.14-2019.4.18)] 2019 Joint Conference of the IEEE International Frequency Control Symposium and European Frequency and Time Forum (EFTF/IFC) - Laser Frequency Stabilization Based on Spectral-Hole Burning Using Double-Heterodyne Detection
摘要： We report a fractional-frequency stability of σy(τ) ≈1.7 × 10-15 near 1 s timescale based on a spectral hole burning (SHB) laser frequency stabilization technique using a novel detection scheme that offer < 10-16 detection noise capability. The current stability level is attributed to residual temperature fluctuations in the cryostat. In addition, we report preliminary results on the measurement of the sensitivity of the spectral hole to uni-axial mechanical strain, which, combined with accelerometric noise measured in our pulse-tube cryostat set the vibration induced fractional stability limit to < 10-17, regardless specially designed crystal mounts.
关键词： Spectral Hole Burning,Ultra-stable Lasers,Metrology
更新于2025-09-16 10:30:52
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Flexible method for accurate calibration of large-scale vision metrology system based on virtual 3-D targets and laser tracker
摘要： For the purpose of obtaining high-precision in stereo vision calibration, a large-size precise calibration target, which can cover more than half of the field of view is vital. However, large-scale calibration targets are very difficult to fabricate. Based on the idea of error tracing, a high-precision calibration method for vision system with large field of view by constructing a virtual 3-D calibration target with a laser tracker was proposed in this article. A virtual 3-D calibration target that covers the whole measurement space can be established flexibly and the measurement precision of the vision system can be traceable to the laser tracker. First, virtual 3-D targets by calculating rigid body transformation with unit quaternion method were constructed. Then, the high-order distortion camera model was taken into consideration. Besides, the calibration parameters were solved with Levenberg–Marquardt optimization algorithm. In the experiment, a binocular stereo vision system with the field of view of 4 (cid:2) 3 (cid:2) 2 m3 was built for verifying the validity and precision of the proposed calibration method. It is measured that the accuracy with the proposed method can be greatly improved comparing with traditional plane calibration method. The method can be widely used in industrial applications, such as in the field of calibrating large-scale vision-based coordinate metrology, and six-degrees of freedom pose tracking system for dimensional measurement of workpiece, as well as robotics geometrical accuracy detection and compensation.
关键词： error tracing,virtual 3-D target,Large-scale vision metrology system,laser tracker,calibration
更新于2025-09-16 10:30:52