Monday, 15 April, 2013
Cavity-enhanced optical detection of carbon nanotube Brownian motion
S. Stapfner, L. Ost, D. Hunger, J. Reichel, I. Favero, and E. Weig -
Appl. Phys. Lett., Vol. 102 (15), 151910 (2013)
Optical cavities with small mode volume are well-suited to detect the vibration of sub-wavelength sized objects. Here we employ a fiber-based, high-finesse optical microcavity to detect the Brownian motion of a freely suspended carbon nanotube at room temperature under vacuum. The optical detection resolves deflections of the oscillating tube down to 70 pm/Hz1/2. A full vibrational spectrum of the carbon nanotube is obtained and confirmed by characterization of the same device in a scanning electron microscope. Our work extends the principles of high-sensitivity optomechanical detection to molecular scale nanomechanical systems.