From Building an Optical Trapping System to Optimizing Its Beam Profile for Enhanced Axial Trapping

Optical tweezers are a well-established tool for exerting and measuring forces on microscopic particles. For large particles, however, conventional traps often provide only weak confinement. In this work, we combine an optical tweezers system with a research microscope, enabling seamless switching between different imaging modalities while maintaining compatibility with momentum-based force detection. Furthermore, we present a method to predict the outgoing light field for any rotationally symmetric ingoing beam, as well as to numerically optimize the shape of the light field in order to enhance the object-specific trapping performance. Because this approach does not require prior knowledge of the sample properties, it offers a robust and versatile basis for improved axial trapping that is readily applicable in biophysical experiments