Fig. 6.
Switching window optimization. (a) Switching efficiency at different pulse energies and delay times. Larger pulse energies generate larger bubbles for higher switching efficiencies but also larger switching windows that could deflect non-target particles into collection channel. (b) Optimization of the nozzle design helps to increase the switching efficiency by narrowing the switching window to allow smaller bubbles for high purity sorting. (c) An optimized switching window is 25 μsec wide in time which equates to 40 μm in distance at a flow speed of 1.5 m sec−1. The highest switching efficiency of 97% occurs at a laser delay time of 18 μsec and decreases to 1% at 5 μsec and 30 μsec delays.