Laser diode feedback interferometry in flowing Brownian motion system: a novel theory

Wang, Hao; Shen, Jianqi; Wang, B.; Yu, Benli; Xu, Yuhang

doi:10.1007/s00340-010-4041-7

Cited by 17 publications

(8 citation statements)

References 45 publications

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“…However, the literature pertaining to the effect in self-mixing sensors is more limited. The dynamic speckle effect in self-mixing sensors has been experimentally reported by several groups [12][13][14], and a number of models have been proposed [15,16] including a model for the more complex problem of fluid flow with Brownian motion [17].…”

Section: Introductionmentioning

confidence: 99%

Spectral broadening caused by dynamic speckle in self-mixing velocimetry sensors

Kliese¹,

Rakić²

2012

Opt. Express

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Self-mixing laser sensors require few components and can be used to measure velocity. The self-mixing laser sensor consists of a laser emitting a beam focused onto a rough target that scatters the beam with some of the emission re-entering the laser cavity. This 'self-mixing' causes measurable interferometric modulation of the laser output power that leads to a periodic Doppler signal spectrum with a peak at a frequency proportional to the velocity of the target. Scattering of the laser emission from a rough surface also leads to a speckle effect that modulates the Doppler signal causing broadening of the signal spectrum adding uncertainty to the velocity measurement. This article analyzes the speckle effect to provide an analytic equation to predict the spectral broadening of an acquired self-mixing signal and compares the predicted broadening to experimental results. To the best of our knowledge, the model proposed in this article is the first model that has successfully predicted speckle broadening in a self-mixing velocimetry sensor in a quantitative manner. It was found that the beam spot size on the target and the target speed affect the resulting spectral broadening caused by speckle. It was also found that the broadening is only weakly dependent on target angle. The experimental broadening was consistently greater than the theoretical speckle broadening due to other effects that also contribute to the total broadening.

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Section: Introductionmentioning

confidence: 99%

Spectral broadening caused by dynamic speckle in self-mixing velocimetry sensors

Kliese¹,

Rakić²

2012

Opt. Express

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“…The power spectrum can be obtained from the time Fourier transform of the autocorrelation function. The firstorder autocorrelation function, Gt, of a scattered electric field caused by a particle in a flowing Brownian motion system is calculated as [9,10,12] …”

Section: Resultsmentioning

confidence: 99%

“…If information on a dilute sample (for example, the diffusion constant of the particles) can be obtained from the power spectrum, then this system can be applied to the product inspection of medicine and cosmetics in glass bottles on a production line in real time using a self-mixing laser with high optical sensitivity [2][3][4]. We previously conjectured that such a system could be treated as a flowing Brownian motion system in which particles undergoing Brownian motion are transported by uniform flow [8][9][10]. However, it turns out that the power spectrum is not described by a formula for flowing Brownian motion systems.…”

Section: Introductionmentioning

confidence: 99%

Analysis of molecular dynamics of colloidal particles in transported dilute samples by self-mixing laser Doppler velocimetry

et al. 2012

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Colloidal particles in a liquid medium are transported with constant velocity, and dynamic light scattering experiments are performed on the samples by self-mixing laser Doppler velocimetry. The power spectrum of the modulated wave induced by the motion of the colloidal particles cannot be described by the well-known formula for flowing Brownian motion systems, i.e., a combination of Doppler shift, diffusion, and translation. Rather, the power spectrum was found to be described by the q-Gaussian distribution function. The molecular mechanism resulting in this anomalous line shape of the power spectrum is attributed to the anomalous molecular dynamics of colloidal particles in transported dilute samples, which satisfy a nonlinear Langevin equation.

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“…While there is one final issue to note: how many pixels can represent the size of the coherence area in the speckle pattern. For the situation shown in Fig.3, assuming the diameter of the scattering volume is d and the distance away from the detector is R, the size of the coherence area will be: (9) Thus, the number of the pixels for one coherence area is:…”

Section: Discussionmentioning

confidence: 99%

“…The particle diffusion coefficient can be determined by intensity autocorrelation function, from which we can obtain the particle size information. Meanwhile, the measurement method has also been used to characterize the fluid velocity in a flowing Brownian motion system [8,9] . Chowdhury et al has studied the application of DLS to a system of flowing Brownian motion particles and compare the results to a representative system of a suspension of polystyrene latex spheres in water flowing through a tube at known flow rate [10] .…”

Section: Introductionmentioning

confidence: 99%

Particle-size Measurements in a Micro-channel with Image Dynamic Light Scattering Method

Liu¹,

Cai²,

Zhang³

et al. 2015

Procedia Engineering

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Conventional dynamic light scattering (DLS) using a CCD camera as optical area detector (here we called Image Dynamic Light Scattering method, for the data acquired by images ) has been developed successfully. We present a model experiment in a micro-channel to study flowing Brownian motion systems of polystyrene latex particles by using Image Dynamic Light Scattering method (IDLS). The modified correlation function proposed by Chowdhury et al, which is applied to the analysis of extracting the size and velocity of laminar flowing particulate dispersions, is used in the paper to obtain the particle size from the scattered light signals. The new method allows for much shorter measurement time compared to conventional DLS. As the inversion algorithm of polydisperse system is yet very complex, the measurement of the paper is for monodisperse polystyrene latex particles.

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Laser diode feedback interferometry in flowing Brownian motion system: a novel theory

Cited by 17 publications

References 45 publications

Spectral broadening caused by dynamic speckle in self-mixing velocimetry sensors

Spectral broadening caused by dynamic speckle in self-mixing velocimetry sensors

Analysis of molecular dynamics of colloidal particles in transported dilute samples by self-mixing laser Doppler velocimetry

Particle-size Measurements in a Micro-channel with Image Dynamic Light Scattering Method

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