We present an optimized optical tweezers system based upon the conical refraction of circularly polarized light in a biaxial crystal. The described optical arrangement avoids distortions to the Lloyd plane rings that become apparent when working with circularly polarized light in conventional optical tweezers. We demonstrate that the intensity distribution of the conically diffracted light permits optical manipulation of high and low refractive index particles simultaneously. Such trapping is in three dimensions and not limited to the Lloyd plane rings. By removal of a quarter waveplate the system also permits the study of linearly polarized conical refraction. We show that particle position in the Raman plane is determined by beam power, and indicates that true optical tweezing is not taking place in this part of the beam.
|Journal||Proceedings of SPIE - International Society for Optical Engineering|
|Publication status||Published - 2012|
|Event||Optical Trapping and Optical Micromanipulation IX: SPIE NANOSCIENCE + ENGINEERING - San Diego, United States|
Duration: 12 Aug 2012 → 16 Aug 2012