Imaging techniques hold the power to enable measurements of motion of
arbitrarily complex structures in three dimensions.
However, typical imaging methods are slow — most cameras operate at
speeds of 30 or fewer frames per second.
However, MEMS devices, such as the one on the right-hand side of this
image, can move at frequencies ranging from DC well into the megaHertz if
not gigaHertz range.
To image such fast motions with slow cameras, we synchronize a light source
with the stimulus driving the MEMS device, a technique called stroboscopic
By changing the phase of the stimulus waveform at which the light source
flashes, we obtain images of the position of the MEMS device as a function
of stimulus phase.
These images can be played back at any desired speed; here, the device
appears to move about one cycle every two seconds.