Nanophotonic trapping for precise manipulation of biomolecular arrays.

Optical trapping is a powerful manipulation and measurement technique widely used in the biological and materials sciences. Miniaturizing optical trap instruments onto optofluidic platforms holds promise for high-throughput lab-on-a-chip applications. However, a persistent challenge with existing optofluidic devices has been achieving controlled and precise manipulation of trapped particles.

Power-law flow statistics in anisometric (wedge) hoppers.

We find the probability for N particles to exit an anisometric (having unequal dimensions) hopper before jamming to have a broad power-law decay with exponent α = -2, in marked contrast to the exponential decay seen in hoppers with symmetric apertures. The transition from exponential to power law is explained by amodel that assumes particle motion is correlated over a distinct length scale. Hoppers with lengths larger than this length are modeled as a series of adjacent, statistically independent "cells.