Tunable optofluidic switch via hydrodynamic control of laminar flow rate

This letter reports a tunable planar optofluidic switch as illustrated by three laminar flow streams introduced into a focusing chamber. Different width of liquid core can be tuned via the imposed flow rate of these three laminar flow streams. The hydrodynamic tunability of the core-cladding interfaces is the key to realize microscale optical switching via total internal reflection. The optical switching capability is demonstrated having good agreement with optical simulations. The optofluidic optical switch can achieve a switching speed of 1.56 Hz and beyond with the potential for a seamless integration with other lab-on-a-chip devices for optical sensing applications.