New paper – Emergence of Directional Rotation

We have a new paper to appear in ACSPhotonics. Great effort by Rahul Chand, Chaudhary Eksha Rani and Diptabrata Paul from our group. We ask : How & why does directional rotation emerge in an optical trap of thermally active (smaller) + passive colloidal combination ?

By combining light absorbing colloid (smaller one) with a normal colloid (bigger ones), we can observe directional rotation in a 2D optical trap. What determines the rotation direction is the relative position of the active colloid in the assembly.

One can switch the direction of rotation, by changing the relative position of active colloid.

For the rotation to emerge, the symmetry of the colloidal arrangement matters. As you see, if there are two active colloids (smaller ones) are symmetrically positions with respect to passive colloids (bigger one), we do not observe rotation.

There is a lot more interesting stuff and explanation of the observed effect discussed in our paper. You can read the pre-print of the our paper in arxiv : https://arxiv.org/abs/2309.12740

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Author: G.V. Pavan Kumar

Namaste, Hola & Welcome from G.V. Pavan Kumar. I am a Professor of Physics at the Indian Institute of Science Education and Research, Pune, India. My research interests are : (1) Optics & Soft Matter: Optically Induced Forces – Assembly, Dynamics & Function; (2) History and Philosophy of Science – Ideas in Physical Sciences. I am interested in the historical and philosophical evolution of ideas and tools in the physical sciences and technology. I research the intellectual history of past scientists, innovators, and people driven by curiosity, and I write about them from an Indian and Asian perspective. My motivation is to humanize science. In the same spirit, I write and host my podcast Pratidhvani – Humanizing Science.

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