High-precision and large-range deflection of light beams with fast steering mirrors

Fast steering mirrors (FSMs) offer a potential alternative for large-range deflection of light beams. However, for a large-stroke FSM, its pointing precision is unacceptably deteriorated due to the actuator non-uniformity, mechanical axis coupling, and the coupling of line-of-sight (LOS) kinematics. This Letter proposes a comprehensive beam-pointing algorithm by decoupling the LOS kinematic model and establishing a two-dimensional correction mapping to compensate for the non-uniformity and mechanical coupling. Moreover, the incident angle is calibrated by a non-contact method to construct the LOS kinematic model accurately. The experimental results proved that the beam-pointing accuracy can achieve a sub-milliradian level within the square field of regard (FOR) of +/- 25 degrees horizontally and +/- 14 degrees vertically. A pointing error of 0.87 mrad can be guaranteed within the horizontal range of -30 degrees to 36 degrees and the vertical range of +/- 24 degrees. Therefore, the proposed method can achieve high-precision beam pointing in a large FOR and contributes to the miniaturization of optical systems. (c) 2024 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.