A light detection and ranging system includes a mirror unit rotating around a scan axis. The mirror unit includes a receiving portion and a transmitting portion offset by an angle about the scan axis relative to a surface plane of the receiving portion. Respective centroids of the receiving and transmitting portions are positioned at a common point on the scan axis while the receiving and transmitting portions rotate around the scan axis. A transmitter transmits a light pulse toward the mirror unit. The transmitting portion is positioned to reflect the light pulse toward a target. A receiver is positioned to reflect the light pulse reflected from the target toward the receiver. The angle offset compensates for a change between a cone of illumination of the transmitting portion and a field-of-view of the receiving portion resulting from the rotation of the mirror unit.