Physics & Astronomy Professor Luis A. Orozco, University of Maryland and Joint Quantum Institute: "Optical Nanofibers: Some Experiments in Optomechanics"

Optical nanofibers are produced by gradually reducing an ordinary single-mode optical fiber to half-micron diameters, less than the typical wavelength we use at 780 nm. We have studied the optomechanical coupling between the angular momentum produced by polarized light and the torsional mode one of those nanofibers. We have observed significant changes, decrease and increase, in the thermal noise of the fundamental torsional mode depending on the angle of polarization with respect to the apparent birefringence axes of the nanofiber. We measure the thermal noise reductions with the Maxwell-Boltzmann distribution of amplitude fluctuations and show cooling by more than a factor of five from room temperature. This cooling happens to all the torsional modes and is free of any optical cavity, opening new avenues to optomechanical investigations.