Optical tweezers is a very useful tool in physics, chemistry and biology. Although translational motion of trapped particles have been extensively studied, rotations are also being studied more recently. Of the rotations, in-plane or yaw motion has been developed over the last couple of decades. In this thesis, we explore yaw motion first and then move on to explore the first out-of-plane rotation which we call pitch motion in the nomenclature of the airlines.
We study the suitability of the cylindrical approximation for spherical particles executing yaw rotation in the first chapter. Then we find new methods to generate yaw rotations with low ellipticity beams. Then we study adhesivity of surfaces using yaw rotations. We move on to detect pitch motion at high resolution and explore cell biological applications. Lastly, we explore strategies for calibration of optical tweezers inside cells.