Study on multilayered coatings of a macroscopic optical force transducer

With the advancement of optical force research at the macroscopic scale, an increasing number of specialized devices have been developed. For such devices, multilayered dielectric coatings with ultrahigh reflectivity, together with precisely predictable optical forces, are essential for ensuring overall performance. This study establishes a theoretical framework for calculating and analyzing optical forces in multilayered coatings by integrating the layer-cavity matrix method with the Maxwell stress tensor. The framework enables precise analysis of optical force distribution with nanometer accuracy. Based on this method, specialized multilayered coatings alternating between silicon dioxide and titanium dioxide were designed and fabricated. The results show that within the 0°-8° incident-angle range, the optical force exhibits excellent robustness to variations in incident angle and polarization, with optical force uncertainty better than 2.0%. This significantly improves the applicability of high-power lasers in macroscopic optical force devices. As the incident angle increases to 30°, the angular sensitivity of the optical force gradually increases, particularly under TM polarization, which provides important references for precise control and enhancement of optical forces. This study is important for fundamental research of the optical force at the macroscopic scale, and is valuable for precision measurements and metrology applications, as well as atomic and close-to-atomic scale manufacturing applications.