Rotational Doppler velocimetry to probe the angular velocity of spinning micro-particles
نویسندگان
چکیده
Laser Doppler velocimetry is a technique used to measure linear velocity, ranging from that of exhaust gases to blood flow. A rotational analog of laser Doppler velocimetry was recently demonstrated, using a rotationally symmetric interference pattern to probe the angular velocity of a spinning object. In this work, we demonstrate the use of a diffraction-limited structured illumination pattern to measure the angular velocity of a micron-sized particle trapped and spinning at tens of Hz in an optical trap. The technique requires no detailed knowledge of the shape of the particle, or the distribution of scatterers within it, and is independent of the particle’s chirality, transparency, and birefringence. The particle is also subjected to Brownian motion, which complicates the signal by affecting the rotation rate and the rotation axis. By careful consideration of these influences, we show how the measurement is robust to both, representing a technique with which to probe the rotational motion of microscale particles.
منابع مشابه
Numerical study on the jet dynamic through centrifuge spinning: influence of angular velocity
متن کامل
I-46: Obstetrical Doppler
Accurate assessment of gestational age, fetal growth, and the detection of fetal and placental abnormalities are major benefits of sonography. Color Doppler can be used to assist in the identification of vascular architecture, detection of vascular pathology and visualization of blood flow changes associated with physiologic processes and disease states. The clinical applications of obstetrical...
متن کاملFabrication of Biodegradable PCL Particles as well as PA66 Nanofibers via Air-Sealed Centrifuge Electrospinning (ASCES)
This study presents a method for fabrication of ultrafine polymeric nanofibers as well as nano/micro particles utilizing centrifugal and electrostatic forces simultaneously. To reduce the diameter and variety of nanofibers produced from solid state polymerized PA66, a unique electrocentrifuge spinning device was utilized with a rotating nozzle and collector, while the fabrication process (spinn...
متن کاملDetection of a spinning object using light's orbital angular momentum.
The linear Doppler shift is widely used to infer the velocity of approaching objects, but this shift does not detect rotation. By analyzing the orbital angular momentum of the light scattered from a spinning object, we observed a frequency shift proportional to product of the rotation frequency of the object and the orbital angular momentum of the light. This rotational frequency shift was stil...
متن کاملOptical angular momentum in a rotating frame.
It is well established that light carrying orbital angular momentum (OAM) can be used to induce a mechanical torque causing an object to spin. We consider the complementary scenario: will an observer spinning relative to the beam axis measure a change in OAM as a result of their rotational velocity? Remarkably, although a linear Doppler shift changes the linear momentum of a photon, the angular...
متن کامل