A pump power exceeding the threshold level for oscillation of the mechanical modes pictured in the upper half of the figure is turned on, and both modes start to oscillate.
The bottom figure shows the actual membrane displacement field, which is the sum of the modes.
As the amplitudes ring up from thermal equilibrium, the two modes jostle for the available optically-furnished mechanical gain, giving rise to motion with a swirling, chaotic appearance.
Ultimately, however, only one mode can win the battle, and the steady-state motion that finally emerges is that of a single mechanical mode.
By controlling the gain characteristics, the experimenters are able to rig the competition to select the winner in advance, or, as pictured here, leave it unpredictable and let Nature decide the outcome.
back to video: Mode Competition Video