Multi-Functional Optical Fiber Tweezers Based on Annular Aperture Array Metasurface

We propose and demonstrate numerically a kind of optical fiber tweezer based on the annular aperture array (AAA) metasurface at the end of an annular core fiber to implement multi-functional optical manipulation by using the finite-element method. The results show that the device can generate single optical potential well (OPW) and double optical potential wells by sharp-edge diffraction of the AAA metasurface under the excitation of short- and long-wavelength lights. Because the distance between the two OPWs remains constant with the incident wavelength, the double OPWs can be used for an optical stretcher. We also show that by switching the incident wavelength and optical power, the microparticle oscillation can be realized in the tunable single OPW. The device can greatly improve the optical trapping ability of single or multiple microparticles, and provides a new idea for the application of optical fiber tweezers in research on micro-nano objects such as cell surgery, DNA unwinding, and targeted drug testing.