Interferometric tracking

2018 ◽  
Author(s):  
Eric M. Furst ◽  
Todd M. Squires
Keyword(s):  
Light Scattering ◽  
Particle Tracking ◽  
High Frequency ◽  
Focal Plane ◽  
Linear Response ◽  
Colloidal Particles ◽  
Linear Response Theory ◽  
Einstein Relation ◽  
Frequency Bandwidth ◽  
Complex Susceptibility

The purpose of this chapter is to present a survey of passive microrheology techniques that are important complements to more widely used particle tracking and light scattering methods. Such methods include back focal plane interferometry and extensions of particle tracking to measure the rotation of colloidal particles. Methods of passive microrheology using back focal plane interferometry are presented, including the experimental design and detector sensitivity and limits in frequency bandwidth and spatial resolution. The Generalized Stokes Einstein relation is derived from linear response theory of the particle position power spectrum and complex susceptibility. Applications of interoferometric tracking include high frequency microrheology and two-point measurements. Lastly, the chapter includes a discussion of rotational passive microrheology and the rotational GSER.

Charge and Size Polydispersity Effects on the Scattering Properties and the High-Frequency Elasticity of Colloids

1989 ◽  
Vol 177 ◽  
Author(s):  
Bruno D'Aguanno ◽  
Rudolf Klein ◽  
Norman J. Wagner
Keyword(s):  
Integral Equation ◽  
Light Scattering ◽  
Binary Mixture ◽  
High Frequency ◽  
Elastic Moduli ◽  
Colloidal Particles ◽  
Multicomponent Mixture ◽  
Static Light Scattering ◽  
Main Peak

ABSTRACTPolydispersity in charge and in size of colloidal particles strongly influences the static light scattering < I(k) >. These effects are calculated by solving the Ornstein-Zernike integral equation together with the thermodynamically consistent Rogers-Young closure for a multicomponent mixture of up to 10 components. The results for < I(k) > for polydisperse systems show significant differences from results obtained by treating the system as an effective monodisperse one. For <I(k) > a large increase is found at small k as well as a shift in the main peak. Finally, using the above results, high-frequency elastic moduli are predicted for a binary mixture.

High-frequency dielectric relaxation of spherical colloidal particles

2003 ◽  
Vol 5 (5) ◽  
pp. 911-915 ◽  
Author(s):  
Reghan J. Hill ◽  
D. A. Saville ◽  
W. B. Russel
Keyword(s):  
Dielectric Relaxation ◽  
High Frequency ◽  
Colloidal Particles

scholarly journals Parallel, linear, and subnanometric 3D tracking of microparticles with Stereo Darkfield Interferometry

2021 ◽  
Vol 7 (6) ◽  
pp. eabe3902
Author(s):  
Martin Rieu ◽  
Thibault Vieille ◽  
Gaël Radou ◽  
Raphaël Jeanneret ◽  
Nadia Ruiz-Gutierrez ◽  
...  
Keyword(s):  
High Precision ◽  
High Throughput ◽  
Single Molecule ◽  
Particle Tracking ◽  
Focal Plane ◽  
Tracking System ◽  
Three Dimensional ◽  
3D Tracking ◽  
Single Molecule Force Spectroscopy ◽  
A New Technique

While crucial for force spectroscopists and microbiologists, three-dimensional (3D) particle tracking suffers from either poor precision, complex calibration, or the need of expensive hardware, preventing its massive adoption. We introduce a new technique, based on a simple piece of cardboard inserted in the objective focal plane, that enables simple 3D tracking of dilute microparticles while offering subnanometer frame-to-frame precision in all directions. Its linearity alleviates calibration procedures, while the interferometric pattern enhances precision. We illustrate its utility in single-molecule force spectroscopy and single-algae motility analysis. As with any technique based on back focal plane engineering, it may be directly embedded in a commercial objective, providing a means to convert any preexisting optical setup in a 3D tracking system. Thanks to its precision, its simplicity, and its versatility, we envision that the technique has the potential to enhance the spreading of high-precision and high-throughput 3D tracking.

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