Ayan Banerjee | IISER-Kolkata - Academia.edu (original) (raw)

Papers by Ayan Banerjee

We describe a simple yet powerful technique of simultaneously measuring both translational and ro... more We describe a simple yet powerful technique of simultaneously measuring both translational and rotational
motion of mesoscopic particles in optical tweezers by measuring the backscattered intensity on a quadrant
photodiode (QPD). While the measurement of translational motion by taking the di erence of the backscattered
intensity incident on adjacent quadrants of a QPD is well-known, we demonstrate that rotational motion can
be measured very precisely by taking the di erence between the diagonal quadrants. The latter measurement
eliminates the translational component entirely, and leads to a detection sensitivity of around 50 mdeg at S/N
of 2 for angular motion of a driven micro-rod. The technique is also able to resolve the translational and
rotational Brownian motion components of the micro-rod in an unperturbed trap, and can be very useful in
measuring translation-rotation coupling of micro-objects induced by hydrodynamic interactions.

Applied Physics Letters, 2001

Journal of The Optical Society of America B-optical Physics, 2004

IEEE/ASME Journal of Microelectromechanical Systems, 2010

Europhysics Letters (epl), 2003

We describe a simple yet powerful technique of simultaneously measuring both translational and ro... more We describe a simple yet powerful technique of simultaneously measuring both translational and rotational
motion of mesoscopic particles in optical tweezers by measuring the backscattered intensity on a quadrant
photodiode (QPD). While the measurement of translational motion by taking the di erence of the backscattered
intensity incident on adjacent quadrants of a QPD is well-known, we demonstrate that rotational motion can
be measured very precisely by taking the di erence between the diagonal quadrants. The latter measurement
eliminates the translational component entirely, and leads to a detection sensitivity of around 50 mdeg at S/N
of 2 for angular motion of a driven micro-rod. The technique is also able to resolve the translational and
rotational Brownian motion components of the micro-rod in an unperturbed trap, and can be very useful in
measuring translation-rotation coupling of micro-objects induced by hydrodynamic interactions.

Applied Physics Letters, 2001

Journal of The Optical Society of America B-optical Physics, 2004

IEEE/ASME Journal of Microelectromechanical Systems, 2010

Europhysics Letters (epl), 2003