scholarly journals Sparsity-Based Recovery of Three-Dimensional Photoacoustic Images from Compressed Single-Shot Optical Detection

2021 ◽  
Vol 7 (10) ◽  
pp. 201
Author(s):  
Dylan Green ◽  
Anne Gelb ◽  
Geoffrey P. Luke
Keyword(s):  
Real Time ◽  
Acoustic Waves ◽  
Simulated Data ◽  
Initial Pressure ◽  
Single Pulse ◽  
High Energy ◽  
Image Sensor ◽  
Single Shot ◽  
Binary Mask ◽  
Time Resolved

Photoacoustic (PA) imaging combines optical excitation with ultrasonic detection to achieve high-resolution imaging of biological samples. A high-energy pulsed laser is often used for imaging at multi-centimeter depths in tissue. These lasers typically have a low pulse repetition rate, so to acquire images in real-time, only one pulse of the laser can be used per image. This single pulse necessitates the use of many individual detectors and receive electronics to adequately record the resulting acoustic waves and form an image. Such requirements make many PA imaging systems both costly and complex. This investigation proposes and models a method of volumetric PA imaging using a state-of-the-art compressed sensing approach to achieve real-time acquisition of the initial pressure distribution (IPD) at a reduced level of cost and complexity. In particular, a single exposure of an optical image sensor is used to capture an entire Fabry–Pérot interferometric acoustic sensor. Time resolved encoding as achieved through spatial sweeping with a galvanometer. This optical system further makes use of a random binary mask to set a predetermined subset of pixels to zero, thus enabling recovery of the time-resolved signals. The Two-Step Iterative Shrinking and Thresholding algorithm is used to reconstruct the IPD, harnessing the sparsity naturally occurring in the IPD as well as the additional structure provided by the binary mask. We conduct experiments on simulated data and analyze the performance of our new approach.

scholarly journals Single-Shot Electro-Optic Sampling on the Temporal Structure of Laser Wakefield Accelerated Electrons

Crystals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 640
Author(s):  
Kai Huang ◽  
Hideyuki Kotaki ◽  
Michiaki Mori ◽  
Yukio Hayashi ◽  
Nobuhiko Nakanii ◽  
...  
Keyword(s):  
Real Time ◽  
Temporal Structure ◽  
High Energy ◽  
High Energy Particle ◽  
Single Shot ◽  
Generation Process ◽  
Laser Wakefield Acceleration ◽  
Wakefield Acceleration ◽  
Electro Optic ◽  
Laser Wakefield

Particle acceleration driven by a high power Ti: sapphire laser has invoked great interest worldwide because of the ultrahigh acceleration gradient. For the aspect of electron acceleration, electron beams with energies over GeV have been generated using the laser wakefield acceleration mechanism. For the optimization of the electron generation process, real-time electron parameter monitors are necessary. One of the key parameters of a high energy particle beam is the temporal distribution, which is closely related with the timing resolution in a pump-probe application. Here, we introduced the electro-optic sampling method to laser wakefield acceleration. Real-time multibunch structures were observed. Careful calculations on the physical processes of signal generation in an electro-optic crystal were performed. Discussions of the methodology are elaborated in detail.

A Time-Resolved Four-Tap Lock-In Pixel CMOS Image Sensor for Real-Time Fluorescence Lifetime Imaging Microscopy

2018 ◽  
Vol 53 (8) ◽  
pp. 2319-2330 ◽  
Author(s):  
Min-Woong Seo ◽  
Yuya Shirakawa ◽  
Yoshimasa Kawata ◽  
Keiichiro Kagawa ◽  
Keita Yasutomi ◽  
...  
Keyword(s):  
Real Time ◽  
Fluorescence Lifetime ◽  
Cmos Image Sensor ◽  
Image Sensor ◽  
Fluorescence Lifetime Imaging Microscopy ◽  
Fluorescence Lifetime Imaging ◽  
Time Resolved ◽  
Lifetime Imaging ◽  
Lock In

scholarly journals Serial snapshot crystallography with a non-monochromatic microbeam

2014 ◽  
Vol 70 (a1) ◽  
pp. C294-C294
Author(s):  
Catherine Dejoie ◽  
Lynne McCusker ◽  
Christian Baerlocher ◽  
Rafael Abela ◽  
Bruce Patterson ◽  
...  
Keyword(s):  
Energy Range ◽  
Simulated Data ◽  
Single Pulse ◽  
Finite Width ◽  
Single Shot ◽  
Crystalline Materials ◽  
X Ray ◽  
Reflection Measurement ◽  
Ewald Sphere ◽  
Diffraction Patterns

X-ray free-electron laser (XFEL) sources create X-ray pulses of unprecedented brilliance and open up new possibilities for the structural characterization of crystalline materials. By exposing a small crystallite (100nm-10μm) to a single ultrafast pulse, a diffraction pattern can be obtained before the crystal is damaged. If such single-pulse diffraction patterns, collected sequentially on many randomly oriented crystallites, are combined, it is possible to determine the structure of the material accurately [1]. One of the drawbacks of this approach is that only a single position of the Ewald sphere is accessed in each pattern, so, because reflections have a finite width, the diffraction condition is not satisfied completely for any of the reflections recorded. The new XFEL source that is being developed in Switzerland (SwissFEL) will provide a broad-bandpass mode with an energy bandwidth of about 4% [2]. By using the full energy range of the SwissFEL beam, a new option for structural studies of crystalline materials becomes possible. In a recent study based on simulated data, we showed that a diffraction experiment with stationary crystallites in such an `extra pink' beam not only increases the number of reflection intensities that can be collected in a single shot, but also overcome the problem of `partial reflection' measurement [3]. To test the viability of the data processing with experimental data, attempts to simulate this 4% bandpass have been carried out on SNBL at ESRF and on the microXAS beamline at SLS. On SNBL, a single crystal was rotated over 360° and a continuous scan of the monochromator over the 4% energy range was performed every 1°. At SLS, a mirror was used to cut off the higher energies of the undulator beam and the energy threshold of a Pilatus detector to eliminate the lower ones. With this setup, a series of randomly oriented crystallites were measured. A comparison of the analysis of these datasets will be presented.

Real-Time Probing of the Synthesis of Colloidal Silver Nanocubes with Time-Resolved High-Energy Synchrotron X-ray Diffraction

2012 ◽  
Vol 116 (21) ◽  
pp. 11842-11847 ◽  
Author(s):  
Sheng Peng ◽  
John S. Okasinski ◽  
Jonathan D. Almer ◽  
Yang Ren ◽  
Lin Wang ◽  
...  
Keyword(s):  
Real Time ◽  
High Energy ◽  
Colloidal Silver ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Silver Nanocubes

Low Energy X-Ray Transmission Images by using a Microfocus X-Ray Tube and a be-Window X-Ray Image Intensifier(XRII)

1998 ◽  
Vol 4 (S2) ◽  
pp. 494-495
Author(s):  
H. Konuma ◽  
K. Kuroki ◽  
K. Kurosawa ◽  
N. Saitoh
Keyword(s):  
Real Time ◽  
Light Element ◽  
Image Intensifier ◽  
High Energy ◽  
Low Energy ◽  
Absorption Coefficients ◽  
Tube Voltage ◽  
Time Resolved ◽  
X Ray ◽  
Time Resolved Measurements

Photographs of x-ray transmission images by x-ray films have been used for observing the inside nondestructively. Further, Imaging Plates(IP) are used for precise measurements of x-ray diffraction patterns. But, these integrating area detectors are not suitable for real time nor time resolved measurements. For real time and time resolved measurements, the X-Ray Image Intensifier(XRII, a large image tube that converts an x-ray image into a visible image) is used for biological x-ray TV systems, x-ray nondestructive inspection systems etc. These TV x-ray image systems require high energy x-rays, x-ray tube voltage of 30 to 150 kV, and show faint contrast for x-ray images of light element substances owing to its low absorption coefficients. However, light elements have intense x-ray absorption coefficients in a low energy x-ray region, x-ray tube voltage of 5 to 20 kV, and give fine contrast for x-ray images of light element substances.

scholarly journals Single-Shot Multicontrast X-ray Imaging for In Situ Visualization of Chemical Reaction Products

2021 ◽  
Vol 7 (11) ◽  
pp. 221
Author(s):  
Margarita Zakharova ◽  
Andrey Mikhaylov ◽  
Vitor Vlnieska ◽  
Danays Kunka
Keyword(s):  
Real Time ◽  
Chemical Reaction ◽  
Single Shot ◽  
Reaction Products ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Imaging ◽  
In Situ Visualization ◽  
Different Time Scales

We present the application of single-shot multicontrast X-ray imaging with an inverted Hartmann mask to the time-resolved in situ visualization of chemical reaction products. The real-time monitoring of an illustrative chemical reaction indicated the formation of the precipitate by the absorption, differential phase, and scattering contrast images obtained from a single projection. Through these contrast channels, the formation of the precipitate along the mixing line of the reagents, the border between the solid and the solution, and the presence of the scattering structures of 100–200 nm sizes were observed. The measurements were performed in a flexible and robust setup, which can be tailored to various imaging applications at different time scales.

Femtosecond Spectroscopy of Chemically Reactive Solids: a Methodology

1992 ◽  
Vol 296 ◽  
Author(s):  
Weining Wang ◽  
Marc M. Wefers ◽  
Keith A. Nelson
Keyword(s):  
Real Time ◽  
Large Amplitude ◽  
Structural Phase ◽  
Excitation Pulse ◽  
Experimental Methodology ◽  
Single Shot ◽  
Lattice Vibrations ◽  
Structural Phase Transitions ◽  
Time Resolved ◽  
Time Basis

AbstractAn experimental methodology for recording femtosecond time-resolved observations of irreversible change in solids is described. The central problem posed is that the trime-dependent evolution must be observed on a single-shot (i.e. real-time) basis since the sample may be permanently altered after each excitation event. Preliminary demonstrations of real-time femtosecond spectroscopic observations are presented. In addition, one-shot data acquisition techniques open up the possibility of excitation intensities that greatly exceed optical damage threshholds of most samples. Since only one excitation pulse is used, cumulative damage mechanisms may be circumvented. Even if the sample is damaged in a single shot, in some cases the events of interest may be observed before damage occurs. The use of timed sequences of high-intensity excitation pulses to drive large-amplitude, coherent lattice vibrations is discussed. If successful, such large-amplitude lattice vibrations could assist crystalline chemical reactions or structural phase transitions.

scholarly journals Real-time Hall-effect detection of current-induced magnetization dynamics in ferrimagnets

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
G. Sala ◽  
V. Krizakova ◽  
E. Grimaldi ◽  
C.-H. Lambert ◽  
T. Devolder ◽  
...  
Keyword(s):  
Hall Effect ◽  
Real Time ◽  
Hall Resistance ◽  
Single Shot ◽  
Switching Speed ◽  
Time Resolved ◽  
Pump Probe ◽  
Topological Quantum ◽  
Transverse Resistance ◽  
Hall Effect Measurements

AbstractMeasurements of the transverse Hall resistance are widely used to investigate electron transport, magnetization phenomena, and topological quantum states. Owing to the difficulty of probing transient changes of the transverse resistance, the vast majority of Hall effect experiments are carried out in stationary conditions using either dc or ac. Here we present an approach to perform time-resolved measurements of the transient Hall resistance during current-pulse injection with sub-nanosecond temporal resolution. We apply this technique to investigate in real-time the magnetization reversal caused by spin-orbit torques in ferrimagnetic GdFeCo dots. Single-shot Hall effect measurements show that the current-induced switching of GdFeCo is widely distributed in time and characterized by significant activation delays, which limit the total switching speed despite the high domain-wall velocity typical of ferrimagnets. Our method applies to a broad range of current-induced phenomena and can be combined with non-electrical excitations to perform pump-probe Hall effect measurements.

The promises and perfidy of cryomicroscopy and analysis

1994 ◽  
Vol 52 ◽  
pp. 382-383
Author(s):  
Patrick Echlin
Keyword(s):  
Low Temperature ◽  
High Energy ◽  
Short Paper ◽  
List Type ◽  
Time Resolved ◽  
Energy Beam ◽  
Cellular Analysis ◽  
Dissolved Ions ◽  
Embedding Medium ◽  
Low Temperature Microscopy

The unusual title of this short paper and its accompanying tutorial is deliberate, because the intent is to investigate the effectiveness of low temperature microscopy and analysis as one of the more significant elements of the less interventionist procedures we can use to prepare, examine and analyse hydrated and organic materials in high energy beam instruments. The promises offered by all these procedures are well rehearsed and the litany of petitions and responses may be enunciated in the following mantra.Vitrified water can form the perfect embedding medium for bio-organic samples.Frozen samples provide an important, but not exclusive, milieu for the in situ sub-cellular analysis of the dissolved ions and electrolytes whose activities are central to living processes.The rapid conversion of liquids to solids provides a means of arresting dynamic processes and permits resolution of the time resolved interactions between water and suspended and dissolved materials.The low temperature environment necessary for cryomicroscopy and analysis, diminish, but alas do not prevent, the deleterious side effects of ionizing radiation.Sample contamination is virtually eliminated.

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