Manipulation force analysis of nanoparticles with ultra-high numerical aperture metalens

Abstract

Metalens optical tweezers technology has several advantages for manipulating micro-nano particles and high integration. Here, we used particle swarm optimization (PSO) to design a novel metalens tweezer, which can get 3-dimensional trapping of particles. The numerical aperture (NA) of the metalens can reach 0.97 and the average focusing efficiency is 44%. Subsequently, we analyzed the optical force characteristics of SiO2 particles with a radius of 350 nm at the focal point of the achromatic metalens. We found the average maximum force of SiO2 particles in the x-direction and z-direction to be 0.88 pN and 0.72 pN, respectively. Compared with the dispersive metalens, it is beneficial in maintaining the constant of optical force, the motion state of trapped particles, and the stability of the trapping position.

Metalens in Improving Imaging Quality: Advancements, Challenges, and Prospects for Future Display

“…When designing a high NA metalens, the p conforms to the Formula (8), which can prevent spherical aberration to improve the resolution of the imaging. [124][125][126][127][128][129][130][131][132][133] As an illustration, Khorasan et al created titanium dioxide meta-atoms on a silicon dioxide substrate in 2016, a meta-atom with a p of 430 nm was utilized to create a metalens with NA of 0.8 when 𝜆 d was 660 nm, and a nanotarget can be easily identified by the smallest distance between neighboring holes as illustrated in Figure 9 (a). [20] Then, in 2017, Chen et al developed a meta-atom with a p of 150 nm at 𝜆 d of 405 nm, as shown in Figure 9 (b), the oil-soaked metalens had a NA of 1.35, and the Harvard logo can be scanned clearly by the metalens-equipped microscope.…”

Design of the achromatic vortex metalens based on phase change material with two-layer two-phase modulation

“…Metasurfaces can be used to develop various optical devices, including metalens, 7 , 11 – 13 vortex generators, 14 – 16 digitally encoded metasurface, 17 , 18 and polarization conversion 19 – 24 Therefore, the device design based on metasurface is considered as a promising technology to realize practical nanofunctional devices.…”

“…Currently, the main applications based on metalenses are high numerical aperture metalenses, 22 , 23 achromatic metalenses, 24 , 25 and multifocal metalenses 26 . Chromatic aberration is the phenomenon of deviation of the focal point in the same plane when light beams of different wavelengths are incident.…”

Millimeter-wave metalens with extended depth of focal on the short focal length

“…Particularly, metasurfaces can regulate the phase, amplitude, and polarization of electromagnetic waves by introducing phase mutations. Many metasurface devices have been developed in the literature, such as metalens [3][4][5][6][7][8][9], holographic metasurfaces [10][11][12][13][14][15][16], vortex beam generators [17][18][19][20][21], absorbers [22][23][24][25][26], etc. The combination of the subwavelength size and facile fabrication of metasurfaces renders them potentially useful for miniaturized applications.…”

“…Let the direction away from the metalens be the positive direction. Equation (4) means that as the ring radius increases, the focus moves toward the positive direction; equation (5) indicates that as the ring radius increases, the focus moves toward the negative direction, as depicted in figure 2.…”