Laser coarse-fine coupling tracking by cascaded rotation Risley-prism pairs

Area of Science:

• Optics and Photonics
• Laser Technology
• Precision Engineering

Background:

• Rotation Risley prisms offer high precision and dynamic performance for laser tracking.
• Existing methods may have limitations in achieving both wide field-of-view coarse tracking and narrow field-of-view fine tracking simultaneously.

Purpose of the Study:

• To propose a novel laser coarse-fine coupling tracking method using two pairs of rotation Risley prisms.
• To enhance laser tracking precision and dynamic performance.
• To enable both forward and inverse tracking functions.

Main Methods:

• Utilizing two pairs of rotation Risley prisms with different wedge angles for cascaded coarse-fine tracking.
• Developing an inverse algorithm combining the two-step method and Newton's iterative method for inverse tracking.
• Implementing a motion switching strategy based on inverse solutions to steer the laser beam.

Main Results:

• The second pair of prisms with a narrower wedge angle enables higher precision tracking within a narrower field of view.
• The proposed inverse algorithm successfully solves the inverse tracking problem for the coarse-fine coupling system.
• Demonstrated ability to steer the laser beam along desired trajectories using the motion switching strategy.

Conclusions:

• The cascaded rotation Risley prism pairs effectively perform laser coarse-fine coupling tracking.
• The novel method enhances precision and dynamic performance in laser tracking applications.
• The developed inverse algorithm and motion switching strategy are validated experimentally.