Active Beam Expander with Positioning Gimbal

Active Beam Expander with Positioning Gimbal :

This project required delivery of a High Energy Laser Testbed Optical Telescope with a three-axis gimbal positioning system. This system includes a 12-inch (30-cm) on-axis telescope with a electromechanically focused secondary mirror and a Magneto-Hydrodynamic Inertial Reference Unit (MIRU) that produces a reference laser beam for feedback into a pointing stabilization system. The secondary mirror is moved for focus using a custom flexure mechanism optimized for high lateral stiffness and smooth motion.

The Positioning Gimbal is designed to point the telescope and acquisition sensor package in elevation and azimuth and provide a platform for testing and evaluation of beam control. When combined, these systems provide an extremely capable means of focusing a high energy laser beam down range.

During development, WMD was required to constantly balance the high performance nature of this project with the limitations of manufacturing a complicated and potentially dangerous product. Working with high-intensity lasers, potentially greater than 10 kw, required designers to incorporate extra layers of control and safety.


The original design called for moving the primary mirror for focus adjustment. Once this design was implemented it proved to be problematic, so the primary focusing system was re-designed to be a much simpler manual system. With the manual system, the primary can be focused and then locked in place, thereby eliminating the need to re-adjust the mirror. All other necessary focusing can be achieved by the secondary mirror focusing mechanism mentioned above.

Related Projects

400-mm Aperture
Elevation-Over-Azimuth Scanner

Beam Expander Telescope

ADAM Beam Expander

DAWN Beam Expander