Seminar by Prof Banerjee 'The ‘light’ machine: Manipulation of mesoscopic systems using optical tweezers'

Speaker:
Dr. Ayan Banerjee
Associate Professor, Department of Physical Sciences, IISER Kolkata, India

Seminar Title:
The ‘light’ machine: Manipulation of mesoscopic systems using optical tweezers

Abstract:
Optical tweezers or the ‘light’ machine show great versatility in the controlled manipulation of mesoscopic matter, and thus have multifarious uses in many branches of science. We have developed several tweezers systems in IISER Kolkata, which are capable of using mesoscopic matter in a variety of applications, and to study some very exotic but intrinsic properties of light itself. I will describe some of our recent work in this direction, which will include both basic instrumentation and applications. For the instrumentation, I will talk about our work on measuring the axial motion of trapped particles with very high precision using a back-focal plane interferometric technique [1]. I will then move on to very interesting studies on the spin-orbit interaction and the spin Hall shift in optical tweezers that we can actually enhance by a very simple yet ingenious manner, so as to impart completely controllable translation and rotation to trapped objects [2,3]. I will conclude with a new technique of lithography that we have developed using laser induced micro-bubbles by self-assembly of material due to convective flows produced by the bubble [4]. The latter has been used to develop catalytic chips [5] and solution processed electronic circuits on a glass substrate, and holds great promise in a variety of low cost but high resolution lithography applications.

References:
[1] Probing the dynamics of an optically trapped particle by phase sensitive back focal plane interferometry, Basudev Roy, Sambit Bikas Pal, Arijit Haldar, Ratnesh Kumar Gupta, Nirmalya Ghosh, and Ayan Banerjee*, Optics Express 20, 8317 (2012).
[2] Controlled transportation of mesoscopic particles by enhanced spin orbit interaction of light in an optical trap, Basudev Roy, Nirmalya Ghosh, S. Dutta Gupta, Prasanta K. Panigrahi, Soumyajit Roy, and Ayan Banerjee**, Physical Review A 87, 043823 (2013).
[3] Enhanced topological phase and spin Hall shifts in an optical trap, Basudev Roy, Nirmalya Ghosh, Ayan Banerjee **, S. Dutta Gupta, and Soumyajit Roy, New J. Phys. 16, 083037 (2014).
[4] Self-Assembly of Mesoscopic Materials to form Controlled and Continuous Patterns by Thermo-Optically Manipulated Laser Induced Microbubbles, Basudev Roy, Manish Arya, Preethi Thomas, Julius Konstantin Jürgschat, Venkat Rao, Ayan Banerjee, Chilla Malla Reddy, and Soumyajit Roy, ‘, Langmuir 29, 14733 (2013) doi: 10.1021/la402777e.
[5] Site Specific Supramolecular Heterogeneous Catalysis by Optically Patterned Soft Oxometalate - Porous Organic Framework (SOM-POF) Hybrid on a Chip, P. Thomas, C. Pei, B. Roy, S. Ghosh, S. Das, A. Banerjee**, T. Ben, S. Qiu and S. Roy, J. Mater. Chem. A 3, 1431, (2015).