Cavity optoelectromechanical regenerative amplification
  Cavity optoelectromechanical regenerative amplification is demonstrated. An optical cavity enhances mechanical transduction, allowing sensitive measurement even for heavy oscillators. A 27.3 MHz mechanical mode of a microtoroid was linewidth narrowed to 6.6\pm1.4 mHz, 30 times smaller than previously achieved with radiation pressure driving in such a system. These results may have applications in areas such as ultrasensitive optomechanical mass spectroscopy. 
Michael A. Taylor, Alex Szorkovszky, Joachim Knittel, Kwan H. Lee,   Terry G. McRae, and Warwick P. Bowen
physics.ins-det cond-mat.mes-hall physics.optics quant-ph