Fig. 4: Reconfigurable particle steering in periodic patterns.
From: Three-dimensional optofluidic control using reconfigurable thermal barriers
a, Periodic arrangement of optofluidic pillars alters the initial particle distribution, showing resemblance to a Galton board experiment. b, Particles move from top to bottom through the periodic optofluidic pattern with an irregular starting distribution, resulting in a binomial distribution of particle positions at the bottom (after normalization), which approaches a normal distribution (black line) for many trials (>200). This behaviour is independent of particle size, demonstrated here for diameters of dp = 5 μm sedimenting at vg = 12.7 μm s−1 (dx = 27 μm and dy = 30 μm) and dp = 4 μm at vg = 8.2 μm s−1 (dx = 24 μm and dy = 27 μm). c, By laterally shifting consecutive rows of pillars by dx/3, the pattern of the particle output distribution can be skewed, bearing similarities to DLD experiments for particle sorting. d, Larger particles (dp = 6 μm, vg = 18.4 μm s−1) are displaced up to 52% in experiments (60% in simulations) towards the bottom-right segment, whereas smaller particles (dp = 4 μm, vg = 8.2 μm s−1) are less deflected (31% experiments, 35% simulations), effectively separating the two species. This behaviour is observed in both experiments and simulations. Scale bars, 10 μm (experiment); 20 μm (simulations).
