High speed lidar via GHz gated photon detector and locked but unequal optical pulse rates.

High speed and high sensitivity time-of-flight lidar is demonstrated by judiciously choosing the repetition rates of a pulsed optical source and the gate rate of a GHz gated single photon detector. Sub-mm ranging can be performed in sub-ms time scales at low received powers. We also demonstrate a method to extend the unambiguous measurement range by simultaneously transmitting multiple optical pulse rates and measuring the return signal with a single detector.