Vibration detection by observation of speckle patterns

2014 ◽  
Vol 53 (5) ◽  
pp. 931 ◽  
Author(s):  
Silvio Bianchi
Keyword(s):  
Vibration Detection ◽  
Speckle Patterns

Real-time high sensibility vibration detection based on phase correlation of line speckle patterns

2022 ◽  
Vol 148 ◽  
pp. 107759
Author(s):  
Xueyuan Huang ◽  
Wei Guo ◽  
Rui Yu ◽  
Xiaozhong Wang
Keyword(s):  
Real Time ◽  
Phase Correlation ◽  
Vibration Detection ◽  
Speckle Patterns

Laser Oscillation in Aggregates of Ultrasmall Si Nanoparticles

2002 ◽  
Vol 728 ◽  
Author(s):  
Munir H. Nayfeh
Keyword(s):  
Stimulated Emission ◽  
Gaussian Beams ◽  
Single Particles ◽  
Nonlinear Characteristics ◽  
Femtosecond Radiation ◽  
Highly Nonlinear ◽  
Line Narrowing ◽  
Si Nanoparticles ◽  
Speckle Patterns ◽  
Spectral Line Narrowing

AbstractWe dispersed electrochemically etched Si into ultrabright ultrasmall nanoparticles, with brightness higher than fluorescein or rhodamine. The emission from single particles is readily detectable. Aggregates or films of the particles exhibit emission with highly nonlinear characteristics. We observe directed blue beams at ∼ 410 nm between faces of aggregates excited by femtosecond radiation at 780 nm; and at ∼ 610 nm from aggregates of red luminescent Si nanoparticles excited by radiation at 550-570 nm from a mercury lamp. Intense directed Gaussian beams, a pumping threshold, spectral line narrowing, and speckle patterns manifest the emission. The results are analyzed in terms of population inversion and stimulated emission in quantum confinement-induced Si-Si dimer phase, found only on ultrasmall Si nanoparticles. This microlasing constitutes an important step towards the realization of a laser on a chip.

Thermal stresses applied on helicopter blades useful to retrieve defects by means of infrared thermography and speckle patterns

2020 ◽  
Vol 18 ◽  
pp. 100511
Author(s):  
F. López ◽  
S. Sfarra ◽  
A. Chulkov ◽  
C. Ibarra-Castanedo ◽  
H. Zhang ◽  
...  
Keyword(s):  
Infrared Thermography ◽  
Thermal Stresses ◽  
Helicopter Blades ◽  
Speckle Patterns

scholarly journals Image reconstruction through a multimode fiber with a simple neural network architecture

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Changyan Zhu ◽  
Eng Aik Chan ◽  
You Wang ◽  
Weina Peng ◽  
Ruixiang Guo ◽  
...  
Keyword(s):  
Neural Network ◽  
Image Reconstruction ◽  
Network Architecture ◽  
Neural Network Architecture ◽  
Training Time ◽  
Modal Dispersion ◽  
Multimode Fibers ◽  
Speckle Patterns ◽  
Hidden Layer ◽  
Simple Neural Network

AbstractMultimode fibers (MMFs) have the potential to carry complex images for endoscopy and related applications, but decoding the complex speckle patterns produced by mode-mixing and modal dispersion in MMFs is a serious challenge. Several groups have recently shown that convolutional neural networks (CNNs) can be trained to perform high-fidelity MMF image reconstruction. We find that a considerably simpler neural network architecture, the single hidden layer dense neural network, performs at least as well as previously-used CNNs in terms of image reconstruction fidelity, and is superior in terms of training time and computing resources required. The trained networks can accurately reconstruct MMF images collected over a week after the cessation of the training set, with the dense network performing as well as the CNN over the entire period.

Micro-vibration detection with heterodyne holography based on time-averaged method

2017 ◽  
Author(s):  
XiaoDong Qin ◽  
Feng Pan ◽  
ZongHui Chen ◽  
XueQin Hou ◽  
Wen Xiao
Keyword(s):  
Vibration Detection ◽  
Micro Vibration

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.

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