The Spectral Analysis of Dynamic Laser Speckle Patterns Generated by Brownian Particle Suspensions: A Stroboscopic Effect Based Filtering Technique

<table>(a) The frame-wise variance of the pixel-averaged intensity in the ROI versus the modulation frequency for 0.69 <i>μ</i>m (open squares) and 2.08 <i>μ</i>m (solid circulars) particles. The solid lines are the Lorenztian spectral functions generated by the curve fit. (b) The bandwidths of the power spectrums obtained from the curve fit versus the actual particle diameters. The error bars are the uncertainties in <svg height="11.6375" id="M47" style="vertical-align:-0.13794pt" version="1.1" viewbox="0 0 21.862499 11.6375" width="21.862499" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
<g transform="matrix(.017,-0,0,-.017,.062,11.362)"><path d="M600 0h-557v24l268 633l28 8l261 -641v-24zM497 50l-194 489l-196 -489h390z" id="x394"></path></g><g transform="matrix(.017,-0,0,-.017,10.959,11.362)"><path d="M615 290q0 -148 -114 -245q-65 -57 -125 -57q-39 0 -62 27t-29 70q-31 -41 -72 -69t-74 -28q-49 0 -82.5 43t-33.5 124q0 97 55 174.5t148 124.5l15 -24q-59 -45 -94 -113t-35 -146q0 -58 19.5 -88.5t48.5 -30.5q33 0 62 34.5t45 101.5q16 73 20 135l80 17l5 -6
q-11 -37 -23.5 -100t-12.5 -92q0 -47 16.5 -71.5t44.5 -24.5q62 0 95.5 67t33.5 160q0 107 -63 152l1 9q14 14 45 14q29 0 57.5 -44t28.5 -114z" id="x1D714"></path></g>
</svg>, produced by the least-square curve fitting procedure. The solid dots give the bandwidths obtained using the conventional intensity correlation analysis for dynamic speckle patterns recorded at a sampling rate of 120 Hz.</table>

Advances in Optics

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Figure 4

Figure 4: The Spectral Analysis of Dynamic Laser Speckle Patterns Generated by Brownian Particle Suspensions: A Stroboscopic Effect Based Filtering Technique 

Figure 4 | The Spectral Analysis of Dynamic Laser Speckle Patterns Generated by Brownian Particle Suspensions: A Stroboscopic Effect Based Filtering Technique 