Beam steering in waveguide arrays

We demonstrate that highly efficient beam steering and switching can be achieved in thermo-optic waveguide arrays. For a given initial excitation, we find the position of the output field to depend on the transverse temperature gradient. By changing this gradient, we manage to steer the beam across the entire array. Diffractive spreading is almost suppressed and the beam retains its initial shape. (C) 2002 American Institute of Physics.