Slow-light lidar scans independently in two dimensions

Researchers from the University of Rochester (Rochester, NY) and the University of Ottawa (Ottawa, ON, Canada) who had previously demonstrated the one-dimensional (1D) steering of a lidar beam using slow light have now used two independent slow-light mechanisms to steer a lidar beam in two dimensions. Their previous system had used dispersive delay for 1D steering; to this, they have now added stimulated Brillouin scattering (SBS) for steering in the orthogonal dimension.

The original 1D system had three apertures (channels) in a row; the 2D system has three channels also, but arranged in an L shape. (These later versions can have many more channels.) The SBS generator includes 3.3 km of dispersion-shifted fiber (DSF) with a 10.5 GHz Brillouin frequency shift. An SBS slow-light module consists of 2.2 km of DSF with a counterpropagating pump field. Controlling the power of the pump field tunes the delay. Tests showed precise phase-locking among all three channels; simulated steering in the x and y directions applied by translation stages were independently compensated by the two delay mechanisms. Contact Zhimin Shi at [email protected].