Development of piezoelectric fast steering mirror with tilt error compensation for portable spectroscopic sensor

Fast steering mirror, a key component that can compensate for the distortion of the optical axis, plays an essential role in portable spectroscopic sensors. Because the performance of the fast steering mirror has a great influence on the accuracy of the interferometer in the spectroscopic sensor, it is important to verify whether it can satisfy the design requirements by evaluating the performance. In this study, a piezoelectric fast steering mirror with high-resolution and high-speed tilting capability for a portable spectroscopic sensor was fabricated and tested. Design requirements such as steering angle, resolution, and frequency range were set for portable spectroscopic sensors and elastic guide structures actuated by piezoelectric actuators were proposed. Before fabrication, the performances of the proposed fast steering mirror were examined by the finite element method. To verify the proposed fast steering mirror, a prototype was manufactured with a size of 24.5 mm × 24.5 mm × 37.4, including a mirror with a diameter of 20 mm and thickness of 3 mm. This prototype can provide the sufficient convenience for mounting on a spectroscopic sensor for gas monitoring at a distance. Its performance was tested, confirming a steering range of 0.56°, resolution of 1.27 µrad seconds and natural frequency of 282 Hz. In addition, through a performance evaluation test using a visible light laser on an optical test bed, the ability to compensate the tilt error within a few seconds was confirmed for its applicability to actual spectroscopic interferometer products in the future.