- 标题
- 摘要
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- 实验方案
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Inverse projected-fringe technique for measurement of dimensions and surface profile of axisymmetric objects
摘要： An inverse projected-fringe technique based on simulating the system of a projector-part-camera is proposed for an on-machine inspection of axisymmetric parts. Parts considered for this study are relatively large, have high specular surfaces and have sharp slopes. A computer simulation-based method and the CAD model of the part was used to produce the inverse fringes as well as to find an appropriate trace passing through the symmetrical axis of the part that offers the best signal to noise ratio. This technique measures the deviation from a master-part and provides an accuracy of better than 10 microns for the part with a radial dimension of about 10 cm. It is shown that the proposed technique improves the signal to noise ratio and the repeatability of the system compared to the standard fringe projection technique, in particular for the areas with a steep slope.
关键词： Fringe projection,Structured light,Inverse fringe projection,Optical metrology,Quality control
更新于2025-09-23 15:21:01
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Laser Scanning Confocal Microscopy 3D Surface Metrology Applications
摘要： Surface metrology, measurement of solid surfaces topography, has become an important topic for many material scientists and engineers. Characterization of the surfaces can help researchers find new functional materials, improve device performance and so forth. ‘Seeing is believing.’ Visualization of fine 3-dimensional (3D) details of surfaces is critical in surface metrology studies. Among various observation and measurement techniques, Laser Scanning Confocal Microscopy (LSCM) becomes more and more popular due to the fact that it is non-contact and non-destructive to the samples, requires minimal sample preparation, and efficient automations and provides single nanometer level resolution. In this paper, we will introduce these features in detail, by using Olympus LEXT OLS5000, the newest 3D laser confocal scanning microscope.
关键词： Olympus LEXT OLS5000,3D Surface Metrology,Laser Scanning Confocal Microscopy
更新于2025-09-23 15:19:57
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[IEEE 2019 Compound Semiconductor Week (CSW) - Nara, Japan (2019.5.19-2019.5.23)] 2019 Compound Semiconductor Week (CSW) - Room-Temperature Electrically Pumped InP-based $1.3\boldsymbol{\mu} \mathbf{m}$ Quantum Dot Laser on on-axis (001) Silicon
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： yield estimation,assembly,circuit analysis,metrology sampling,Yield prediction,integrated circuit packaging
更新于2025-09-23 15:19:57
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[IEEE 2019 Compound Semiconductor Week (CSW) - Nara, Japan (2019.5.19-2019.5.23)] 2019 Compound Semiconductor Week (CSW) - Effect of Annealing on The Bottom Cell in GaInP/GaAs/GaInNAsSb Triple Junction Solar Cells by MBE/MOCVD Hybrid Growth
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： yield estimation,assembly,circuit analysis,metrology sampling,Yield prediction,integrated circuit packaging
更新于2025-09-23 15:19:57
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Demonstration of a Reconfigurable Entangled Radio-Frequency Photonic Sensor Network
摘要： Quantum metrology takes advantage of nonclassical resources such as entanglement to achieve a sensitivity level below the standard quantum limit. To date, almost all quantum-metrology demonstrations are restricted to improving the measurement performance at a single sensor, but a plethora of applications require multiple sensors that work jointly to tackle distributed sensing problems. Here, we propose and experimentally demonstrate a reconfigurable sensor network empowered by continuous-variable (CV) multipartite entanglement. Our experiment establishes a connection between the entanglement structure and the achievable quantum advantage in different distributed sensing problems. The demonstrated entangled sensor network is composed of three sensor nodes each equipped with an electro-optic transducer for the detection of radio-frequency (RF) signals. By properly tailoring the CV multipartite entangled states, the entangled sensor network can be reconfigured to maximize the quantum advantage in distributed RF sensing problems such as measuring the angle of arrival of an RF field. The rich physics of CV multipartite entanglement unveiled by our work would open a new avenue for distributed quantum sensing and would lead to applications in ultrasensitive positioning, navigation, and timing.
关键词： distributed sensing,entanglement,quantum metrology,electro-optic transducer,radio-frequency
更新于2025-09-23 15:19:57
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Entangled States of Atomic Solitons for Quantum Metrology
摘要： The formation of multiparticle maximally path-entangled states (known as N00N-states) are considered along with their use in quantum metrology. It is shown how the standard quantum limit can be overcome and the Heisenberg limit can be reached when measuring the linear phase shift. It is also shown how the Heisenberg limit can be overcome when measuring the parameters of a medium in nonlinear quantum metrology.
关键词： quantum metrology,Heisenberg limit,Bose–Einstein condensates,standard quantum limit,N00N-states
更新于2025-09-23 15:19:57
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Towards the LISA backlink: experiment design for comparing optical phase reference distribution systems
摘要： LISA is a proposed space-based laser interferometer detecting gravitational waves by measuring distances between free-floating test masses housed in three satellites in a triangular constellation with laser links in-between. Each satellite contains two optical benches that are articulated by moving optical subassemblies for compensating the breathing angle in the constellation. The phase reference distribution system, also known as backlink, forms an optical bi-directional path between the intra-satellite benches. In this work we discuss phase reference implementations with a target non-reciprocity of at most 2π μrad √Hz?1 for a wavelength of 1064 nm in the frequency band from 0.1 mHz to 1 Hz. One phase reference uses a steered free beam connection, the other one a fiber together with additional laser frequencies. The noise characteristics of these implementations will be compared in a single interferometric set-up with a previously successfully tested direct fiber connection. We show the design of this interferometer created by optical simulations including ghost beam analysis, component alignment and noise estimation. First experimental results of a free beam laser link between two optical set-ups that are co-rotating by ±1° are presented. This experiment demonstrates sufficient thermal stability during rotation of less than 10?4 K √Hz?1 at 1 mHz and operation of the free beam steering mirror control over more than 1 week.
关键词： laser interferometer space antenna,gravitational wave detection,precision metrology,laser interferometry,stray light
更新于2025-09-23 15:19:57
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Absolute flat test using rotated and multi-shifted maps with relative tilt measurement
摘要： In classical three-flat test, error in reference surface can not be identified fully. What we obtain is only the absolute radial profile instead. In addition, at least three flats with similarly high accuracy are required. The test procedures are very complex and it takes a long time and requires high precision adjustment. In this paper, we proposed a new method for absolute test of flatness. There are only two flats used in our method and it does not need precise alignment of the specimens. The method requires multiple translations of the test surface and one 90° rotation step. The relative tilt during translation is measured by a compact wavefront interferometer. We analyze the effect of noise, tilt estimation error and rotation error on reconstruction result. The method is experimentally verified and compared with the direct interferometric result using high precision reference surface.
关键词： Multi-shift and rotation,Surface figure metrology,Absolute testing
更新于2025-09-19 17:15:36
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Optimal Gaussian measurements for phase estimation in single-mode Gaussian metrology
摘要： The central issue in quantum parameter estimation is to find out the optimal measurement setup that leads to the ultimate lower bound of an estimation error. We address here a question of whether a Gaussian measurement scheme can achieve the ultimate bound for phase estimation in single-mode Gaussian metrology that exploits single-mode Gaussian probe states in a Gaussian environment. We identify three types of optimal Gaussian measurement setups yielding the maximal Fisher information depending on displacement, squeezing, and thermalization of the probe state. We show that the homodyne measurement attains the ultimate bound for both displaced thermal probe states and squeezed vacuum probe states, whereas for the other single-mode Gaussian probe states, the optimized Gaussian measurement cannot be the optimal setup, although they are sometimes nearly optimal. We then demonstrate that the measurement on the basis of the product quadrature operators ^X^P + ^P^X, i.e., a non-Gaussian measurement, is required to be fully optimal.
关键词： Gaussian states,Fisher information,optimal measurements,quantum metrology,phase estimation
更新于2025-09-19 17:15:36
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[IEEE 2018 11th Global Symposium on Millimeter Waves (GSMM) - Boulder, CO, USA (2018.5.22-2018.5.24)] 2018 11th Global Symposium on Millimeter Waves (GSMM) - High-Resolution Antenna Near-Field Imaging and Sub-THz Measurements with a Small Atomic Vapor-Cell Sensing Element
摘要： Atomic sensing and measurement of millimeter-wave (mmW) and THz electric fields using quantum-optical EIT spectroscopy of Rydberg states in atomic vapors has garnered significant interest in recent years towards the development of atomic electric-field standards and sensor technologies. Here we describe recent work employing small atomic vapor cell sensing elements for near-field imaging of the radiation pattern of a Ku-band horn antenna at 13.49 GHz. We image fields at a spatial resolution of λ/10 and measure over a 72 to 240 V/m field range using off-resonance AC-Stark shifts of a Rydberg resonance. The same atomic sensing element is used to measure sub-THz electric fields at 255 GHz, an increase in mmW-frequency by more than one order of magnitude. The sub-THz field is measured over a continuous ±100 MHz frequency band using a near-resonant mmW atomic transition.
关键词： atom,microwave,electric field,metrology,quantum sensing,millimeter-wave,THz,antenna,mmW,Rydberg,terahertz,Atomic sensors,antenna characterization
更新于2025-09-19 17:15:36