High-resolution electric speckle pattern interferometry by using only two speckle patterns

2011 ◽  
Author(s):  
Y. Arai ◽  
T. Inoue ◽  
S. Yokozeki
Keyword(s):  
High Resolution ◽  
Speckle Pattern ◽  
Speckle Patterns

SPECKLE STATISTICS IN THE PHOTON LOCALIZATION TRANSITION

2010 ◽  
Vol 24 (12n13) ◽  
pp. 1950-1988 ◽  
Author(s):  
Azriel Z. Genack ◽  
Jing Wang
Keyword(s):  
Steady State ◽  
Probability Distributions ◽  
Speckle Pattern ◽  
Frequency Variation ◽  
Localization Transition ◽  
Classical Waves ◽  
Speckle Patterns ◽  
The Many ◽  
Photon Localization ◽  
State Propagation

We review the statistics of speckle in the Anderson localization transition for classical waves. Probability distributions of local and integrated transmission and of the evolution of the structure of the speckle pattern are related to their corresponding correlation functions. Steady state and pulse transport can be described in terms of modes whose speckle patterns are obtained by decomposing the frequency variation of the transmitted field. At the same time, transmission can be purposefully manipulated by adjusting the incident field and the eigenchannels of the transmission matrix can be found by analyzing sets of speckle patterns for different inputs. The many aspects of steady state propagation are reflected in diverse, but simply related, parameters so that a single localization parameter encapsulates the character of transport on both sides of the divide separating localized from diffusive waves.

X-ray intensity fluctuation spectroscopy measurements of the charge density wave phases of NbSe3

2002 ◽  
Vol 12 (9) ◽  
pp. 3-8
Author(s):  
M. Sutton ◽  
Y. Li ◽  
J. D. Brock ◽  
R. E. Thorne
Keyword(s):  
Charge Density ◽  
Charge Density Wave ◽  
Intensity Fluctuation ◽  
Speckle Pattern ◽  
Equations Of Motion ◽  
Density Wave ◽  
Electrical Currents ◽  
X Ray ◽  
Longitudinal Correlation ◽  
Speckle Patterns

An introduction to X-ray Intensity Fluctuation Spectroscopy (XIFS) is given by describing its relationship to speckle from coherent sources. A brief description of the relationship of XIFS measurements to the underlying equations of motion is given. Preliminary results for the charge density wave (CDW) system NbSe3 are then presented. Static speckle patterns are shown for the $\overrightarrow {Q}_1 = (0 .76$ 0) CDW peak showing that XIFS experiments are possible in this systom provided time constants are long enough. For electrical currents below threshold, a static speckle pattern is observed but for currents above threshold the speckles are smeared out showing movement of the CDW. It is also shown that above threshold, the longitudinal correlation length decreases.

A Quantitative Approach to Speckle Reduction via Frequency Compounding

1986 ◽  
Vol 8 (3) ◽  
pp. 151-164 ◽  
Author(s):  
G.E. Trahey ◽  
J.W. Allison ◽  
S.W. Smith ◽  
O.T. von Ramm
Keyword(s):  
Speckle Pattern ◽  
Imaging Systems ◽  
Center Frequency ◽  
Speckle Reduction ◽  
Optimal Method ◽  
Pattern Change ◽  
Multiple Imaging ◽  
Speckle Patterns ◽  
Contrast Reduction ◽  
Ultrasonic Images

Coherent speckle is a source of image noise in ultrasonic B-mode imaging. The use of multiple imaging frequencies has been suggested as a technique for speckle contrast reduction. This technique involves the averaging of images whose speckle patterns have been modified by a change in the spectrum of the transmitted or received acoustical pulse. We have measured the rate of this speckle pattern change in ultrasonic images as a function of the change in center frequency of the transmitted acoustical pulse. This data is used to quantitatively describe the trade-off of resolution loss versus speckle reduction encountered when frequency compounding is employed and to derive the optimal method of frequency compounding. These results are then used as a basis for describing the overall advisability of frequency compounding in ultrasonic imaging systems. Our analysis indicates that simple frequency compounding is counterproductive in improving image quality.

scholarly journals Focusing a round coherent beam by spatial filtering the horizontal source

2020 ◽  
Vol 27 (6) ◽  
pp. 1528-1538
Author(s):  
Eric M. Dufresne ◽  
Suresh Narayanan ◽  
Ruben Reininger ◽  
Alec R. Sandy ◽  
Larry Lurio
Keyword(s):  
Speckle Pattern ◽  
Spatial Filtering ◽  
Coherent Scattering ◽  
Correlation Spectroscopy ◽  
Two Dimensional ◽  
Array Detectors ◽  
Optical Layout ◽  
Pixel Array ◽  
Speckle Patterns ◽  
Photon Source

This paper illustrates the use of spatial filtering with a horizontal slit near the source to enlarge the horizontal coherence in an experimental station and produce a diffraction-limited round focus at an insertion device beamline for X-ray photon correlation spectroscopy experiments. Simple expressions are provided to guide the optical layout, and wave propagation simulations confirm their applicability. The two-dimensional focusing performance of Be compound refractive lenses to produce a round diffraction-limited focus at 11 keV capable of generating a high-contrast speckle pattern of an aerogel sample is demonstrated. The coherent scattering patterns have comparable speckle sizes in both horizontal and vertical directions. The focal spot sizes are consistent with hybrid ray-tracing calculations. Producing a two-dimensional focus on the sample can be helpful to resolve speckle patterns with modern pixel array detectors with high visibility. This scheme has now been in use since 2019 for the 8-ID beamline at the Advanced Photon Source, sharing the undulator beam with two separate beamlines, 8-ID-E and 8-ID-I at 7.35 keV, with increased partially coherent flux, reduced horizontal spot sizes on samples, and good speckle contrast.

scholarly journals Speckle tweezers for manipulation of high and low refractive index micro-particles and nano-particle loaded vesicles

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ramin Jamali ◽  
Farzaneh Nazari ◽  
Azadeh Ghaffari ◽  
Sabareesh K. P. Velu ◽  
Ali-Reza Moradi
Keyword(s):  
Soft Matter ◽  
Speckle Pattern ◽  
Nano Particle ◽  
Lower Intensity ◽  
Nanoscale Particles ◽  
Micro Particles ◽  
Periodic Potentials ◽  
Speckle Patterns ◽  
Fundamental Research ◽  
Low Refractive Index

Abstract Several fundamental research and applications in biomedicine and microfluidics often require controlled manipulation of suspended micro- and nanoscale particles. Speckle tweezers (ST) by incorporating randomly distributed light fields have been used to control micro-particles with refractive indices higher than their medium and to perform manipulation tasks such as guiding and sorting. Indeed, compared to periodic potentials, ST represents a wider possibility to be operated for such tasks. Here, we extend the usefulness of ST into micro-particles of low index with respect to the surrounding. Repelling of such particles by high intensity regions into lower intensity regions makes them to be locally confined, and the confinement can be tuned by changing the average grain intensity and size of the speckle patterns. Experiments on polystyrenes and liposomes validate the procedure. Moreover, we show that ST can also manipulate the nano-particle (NP)-loaded liposomes. Interestingly, the different interactions of NP-loaded and empty liposomes with ST enable collective manipulation of their mixture using the same speckle pattern, which may be explained by inclusion of the photophoretic forces on NPs. Our results on the different behaviors between empty and non-empty vesicles may open a new window on controlling collective transportation of drug micro-containers along with its wide applications in soft matter.

scholarly journals Analysis of speckle patterns in electronic devices for the monitoring of current changes

2021 ◽  
pp. 1-7
Author(s):  
Yadira Fabiola López-Álvarez ◽  
Ricardo Jara-Ruiz ◽  
Martín Eduardo Rodriguez-Franco ◽  
Sergio Delgado-Guerrero
Keyword(s):  
Statistical Analysis ◽  
Electronic Device ◽  
Optical Measurement ◽  
Speckle Pattern ◽  
Electronic Devices ◽  
Correlation Coefficients ◽  
Second Order ◽  
Junction Temperature ◽  
Good Tool ◽  
Speckle Patterns

Derived from new advances technological focused on the development of highly functional electronic devices; the manufacturers are obliged to the implementation of techniques to monitor their behavior. These techniques can be destructive or non-destructive, taking the analyzed device to the maximum working range. In this investigation report we show of the results obtained in the study of the speckle patterns of a positive voltage regulator, we used the probability density function and the correlation coefficients, as a statistical analysis of first and second order. The analysis was realized in each terminal of the electronic device, with changes in the input current. The result obtained suggest that the first and second order statistical analysis are good tool in a not destructive measurement and that its results can be relationship with the supply current. These changes are present a behavior ascending as the device operates in the junction temperature range; presenting itself as a mechanism for transmission and convection of heat, using the random distribution of speckle pattern, taking to optical measurement as an technique alternative in the study of electronic devices.

Characterization of LIGA Microsystems Using Digital Image Correlation Technique and SEM Imaging

Aerospace ◽  
2005 ◽  
Author(s):  
Helena (Huiqing) Jin ◽  
Wei-Yang Lu ◽  
Jeff Chames ◽  
Nancy Yang
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Speckle Pattern ◽  
Image Correlation ◽  
Specimen Surface ◽  
Correlation Technique ◽  
Sem Images ◽  
Full Field ◽  
Speckle Patterns ◽  
Dic Technique

A new experimental technique was developed to characterize the mechanical properties of LIGA (an acronym from German words for lithography, electroplating, and molding) materials. An advanced imaging capability, scanning electron microscopy (SEM), with an integrated loading stage allows the acquisition of in situ microstructural images at the micro scale during loading. The load is measured directly from a load cell, and the displacement field is calculated from the SEM images based on the digital image correlation (DIC) technique. The DIC technique is a full-field deformation measurement technique which obtains displacement fields by comparing random speckle patterns on the specimen surface before and after deformation. The random speckle patterns are typically generated by applying a thin layer of material with high contrast to a specimen surface. Alternatively, DIC can also be applied using the microstructural features of a surface as texture patterns for correlation. DIC technique is ideally suited to characterize the deformation field of MEMS structures without the need to generate a random speckle pattern, which can be very challenging on the micro and nanoscale. In this paper, the technique is experimentally demonstrated on a LIGA specimen. The digital images showing LIGA surface features acquired during the loading can serve as random patterns for the DIC method. Therefore, full-field displacement and strain can be obtained directly on the specimen and the errors incurred by the testing system can be eliminated.

Measurement of Leadframe Strain in Electrically Active Power Semiconductors

2015 ◽  
Author(s):  
Seth M. Avery ◽  
Robert D. Lorenz
Keyword(s):  
Significant Contribution ◽  
Speckle Pattern ◽  
Surface Displacement ◽  
Experimental Methodology ◽  
Electronic Speckle Pattern Interferometry ◽  
Power Semiconductors ◽  
Active Devices ◽  
Speckle Patterns ◽  
Noise Measurements ◽  
Strain Model

In this work, thermal-mechanical leadframe strain in an electrically active IGBT was measured using electronic speckle pattern interferometry (ESPI). ESPI is a non-contact optical technique capable of high resolution surface displacement measurements. The significant contribution of this paper is an experimental methodology by which strain can be measured in electrically active devices. A 3-D ESPI test stand was developed, combining two cameras to simultaneously capture the local (interconnect level) and global (device level) displacements. Through the combination of incremental sub-loads and mathematical recorrelation of speckle patterns, device power loads have been measured (which would have been otherwise impossible due to speckle decorrelation, which limits measurement of large deformations). A model-based tracking technique was developed from coupled experimental noise measurements and FE modeling — allowing for optimal strain solution to be extracted from noisy displacement results. The developed and experimentally-validated thermal-mechanical FE strain model agreed to within 7% of ESPI strain measurements.

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