Fig. 1. System schematic. A piezoelectric transducer (T) is driven by a sinusoidal waveform, inducing an ultrasonic standing wave in a rectangular channel of a glass microfluidic chip. Flowing particles are delivered from the syringe pump (S), and are acoustically focussed towards the pressure node plane which is located at the half-height of the device. This plane coincides with the focal plane of the imaging objective (O). Optical components include tube lens (L1), illumination optics (L3, 4), white light source (LS), and a fluorescence filter cube set (TFC). A programmable function generator (PFG) controls the angle of the rotating galvo mirror (GM), and the trigger signal for the camera (C1).
