1Shenzhen University, Institute of Microscale Optoelectronics and State Key Laboratory of Radio Frequency Heterogeneous Integration, Nanophotonics Research Center, Shenzhen, China
2Research Institute of Intelligent Sensing, Research Center for Humanoid Sensing, Zhejiang Lab, Hangzhou, China
2Shenzhen University, Institute of Microscale Optoelectronics and State Key Laboratory of Radio Frequency Heterogeneous Integration, Nanophotonics Research Center, Shenzhen, China
3Delft University of Technology, Optics Research Group, Delft, The Netherlands
Nonlinear responses of nanoparticles induce enlightening phenomena in optical tweezers. With the gradual increase in optical intensity, effects from saturable absorption (SA) and reverse SA (RSA) arise in sequence and thereby modulate the nonlinear properties of materials. In current nonlinear optical traps, however, the underlying physical mechanism is mainly confined within the SA regime because threshold values required to excite the RSA regime are extremely high. Herein, we demonstrate, both in theory and experiment, nonlinear optical tweezing within the RSA regime, proving that a fascinating composite trapping state is achievable at ultrahigh intensities through an optical force reversal induced through nonlinear absorption. Integrated results help in perfecting the nonlinear optical trapping system, thereby providing beneficial guidance for wider applications of nonlinear optics.