Observation of Intricate Chiral Optical Force in a Spin-Curl Light Field

Area of Science:

• Optics and Photonics
• Chiral Physics
• Nanotechnology

Background:

• Chiral optical forces are crucial for enantioselective sorting and sensing.
• Current experimental methods using common light waves face challenges in fully demonstrating chiral optical force theorems.
• Existing studies often focus on specific types of chiral forces, limiting a holistic understanding.

Purpose of the Study:

• To elucidate the cooperative significance of multiple optical forces in generating intricate chiral optical forces.
• To investigate the interplay of distinct light properties (transverse spin, Belinfante spin momentum, energy vortex) in a complex spin-curl field.
• To establish a new paradigm for testing the holistic optical-force theorem on chiral particles.

Main Methods:

• Theoretical elucidation of cooperative optical forces.
• Generation of a complex spin-curl light field.
• Experimental measurements of forces on chiral particles.

Main Results:

• Demonstrated the generation of intricate chiral optical forces through the combination of multiple light properties.
• Observed abnormal phenomena, including force sign reversal with particle handedness and correlation with particle size and light helicity.
• Experimental validation of quasi-achiral and chirality-determined forces.

Conclusions:

• The study presents a novel approach to chiral optical forces, moving beyond single-force demonstrations.
• The findings provide a paradigm for testing holistic optical-force theorems on chiral particles.
• The research opens avenues for applications in chiral sensing, sorting, spintronics, and metamaterials.