Pulsed laser triggered high speed microfluidic switch

We report a high speed microfluidic switch capable of achieving a switching time of 70 μsec. The switching mechanism is realized by exciting dynamic vapor bubbles with focused laser pulses in a microfluidic PDMS channel. A time-resolved imaging system has been constructed to capture the nanosecond transient channel wall deformation and the particle flow pattern. A switching of polystyrene microspheres in a Y channel has also been demonstrated. This ultrafast laser triggered switching mechanism has the potential to advance the sorting speed of the state-of-the-art microscale fluorescent activated cell sorting devices for two orders of magnitude.