Utilizing Mode-Division Multiplexing for Multicell Trapping

We propose a novel single-fiber optical tweezers technology based on mode-division multiplexing (MDM) using LP<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</sub>, LP<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub>, and LP<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">21</sub> modes. This method enables effective coupling between multimode fibers (MMFs) and single-mode fibers (SMFs) through precise coaxial splicing. By exciting multiple modes in the MMF and employing the SMF for mode filtering, we selectively retain the LP<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">01</sub>, LP<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub>, and LP<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">21</sub> modes while effectively suppressing higher order modes. Additionally, we have designed and fabricated an abruptly tapered fiber (ATF) probe to converge the beams of different modes, generating distinct focused light fields at the probe’s tip and sides. The simulation and experimental results indicate that this technology can establish multiple stable optical traps, allowing for the effective trapping of several cells. This approach provides precise manipulation tools for studying interactions, such as collective sensing and metabolic cooperation among cells, demonstrating significant application potential, particularly in single-cell analysis, multicellular assembly, and biological micromanipulation.