What are fast steering mirrors used for?

Fast Steering Mirrors

Fast Steering Mirrors (FSMs) are specialized devices that quickly redirect a laser or light beam's path with high precision and speed. They are capable of making very fine angular adjustments to control the beam's direction, essential in a variety of high-speed optical applications.

Applications

• Free-space laser communication systems to maintain the alignment of communication links.
• Optical telescopes and astronomy for correcting atmospheric turbulence distortions in real-time (a technique known as adaptive optics).
• Target tracking and pointing systems in defense for directing laser beams at fast-moving targets.
• Laser materials processing to steer laser beams quickly over a workpiece for cutting, welding, or marking.
• Lidar systems for high-speed scanning and mapping.
• Optical image stabilization, to reduce the blurring of images caused by movement during image capture.

Construction

FSMs typically consist of a mirror mounted on actuators, such as piezoelectric devices, voice coils, or galvanometers. These actuators produce rapid angular motion of the mirror, which in turn redirects the beam. The construction is designed for minimal inertia and high stiffness to achieve the required speed and precision.

Functionality

The core functionality of FSMs is to compensate for disturbances that may affect the path of a light beam. These disturbances can originate from vibrations, thermal fluctuations, or atmospheric conditions. Fast steering mirrors achieve this by utilizing feedback control systems that rapidly adjust the mirror's tilt in response to sensed disturbances. The result is a stabilized beam path that remains accurately aligned with its intended target or sensor.

Advantages of Fast Steering Mirrors

• High speed and responsiveness allowing for real-time corrections.
• High precision in beam positioning and stabilization.
• Ability to work in various environments, including vacuum and space conditions.
• Compact and reliable, with components that are often solid-state or have minimal moving parts.
• Compatible with a wide range of wavelengths and types of light beams.

Considerations

When implementing FSMs, factors such as the control system bandwidth, actuator range and speed, mirror size and inertia, and the overall system latency need to be optimized for the specific application. Ensuring the FSM is properly integrated into the optical system is key for achieving the desired performance.