The optical systems for the transmitter and receiver of a high-power lidar for stratospheric measurements have been designed and analyzed. The system requirements and design results are presented and explained. An important and driving factor of this design was the requirement for a small image diameter in the plane of an optical chopper to allow the high-intensity lidar returns from the lower atmosphere to be shielded from the detection system. Some results relevant to the optical performance of the system are presented. The resulting system has been constructed and is now in operation at the Mauna Loa Observatory, Hawaii, and is making regular measurements of stratospheric ozone, temperature, and aerosol profiles.