A review on optical torques: from engineered light fields to objects

In recent decades, optical micro/nano manipulation has made remarkable strides in the fields of biology and the physical sciences, benefiting from both theoretical and experimental advances in optical forces. The emergence of optical torques has further enhanced the capabilities and possibilities of optical micro/nano manipulation, opening the door to exciting new applications. In this review, we delve into the fundamentals and recent breakthroughs in the realm of optical micro/nano manipulation using optical torques. We introduce the advancements in optical manipulation based on optical torques from engineered light fields and objects, and highlight the latest developments in applying optical torques to cutting-edge physical and biological scenarios, with a special emphasis on the detection and manipulation of biological structures. Finally, we conclude by outlining our vision for the current and future directions of this field, including the integration of optical torque and micro/nano technologies, the utilization of special light fields, and the development of deep-learning-assisted optical torque design.