Varifocal Metalens for Optical Sectioning Fluorescence Microscopy

Abstract

Fluorescence microscopy with optical sectioning capabilities is extensively utilized in biological research to obtain three-dimensional structural images of volumetric samples. Tunable lenses have been applied in microscopy for axial scanning to acquire multiplane images. However, images acquired by conventional tunable lenses suffer from spherical aberration and distortions. Here, we design, fabricate, and implement a dielectric Moirémetalens for fluorescence imaging. The Moirémetalens consists of two complementary phase metasurfaces, with variable focal length, ranging from ∼10 to ∼125 mm at 532 nm by tuning mutual angles. In addition, a telecentric configuration using the Moirémetalens is designed for high-contrast multiplane fluorescence imaging. The performance of our system is evaluated by optically sectioned images obtained from HiLo illumination of fluorescently labeled beads, as well as ex vivo mice intestine tissue samples. The compact design of the varifocal metalens may find important applications in fluorescence microscopy and endoscopy for clinical purposes.

Dielectric metalens for miniaturized imaging systems: progress and challenges

“… a Variable focal length via microelectromechanical systems. Reproduced with permission 130 . Copyright 2021, American Chemical Society.…”

“…The performance of metalenses is degraded by a series of fabrication imperfections. For the sake of high resolution, most metalenses especially those operating in the visible regime have been fabricated by electron-beam lithography (EBL) or focused ion beam (FIB) techniques 201 (including those with millimeter-diameter 35 , 41 , 47 , 65 , 66 , 70 , 71 , 89 , 122 , 128 , 130 , 163 , 202 ). Nevertheless, a typical EBL or FIB process to define large area structures suffers from time-consuming and high costs.…”

Cubic-Phase Metasurface for Three-Dimensional Optical Manipulation

“…Moreover, our metasurface based on beam shaper can be directly integrated with fiber optic probes and microfluidic devices [ 60 , 62 ]. Moreover, a tunable metasurface based on beam shaper can be designed to adjust trapping potentials along the axial direction [ 63 , 64 , 65 ]. Our technique is not limited only to Airy beams, and other exotic light beams can be created from a metasurface with different operation wavelengths, without any additional optical components.…”

Rotational Multiplexing Method Based on Cascaded Metasurface Holography

“…Integrated multilayer metasurface layouts have often been used to achieve kaleidoscopic wavefront control, [38] multispectral achromatic metalenses, [39] image differentiation, [40] Janus metasurfaces with bidirectional functionality, [41][42][43] holography with asymmetric transmission, [44] holography with color printing, [45] and all-optical machine learning frameworks. [46] For cascaded metasurfaces, whose components can be replaced, translated, or rotated, impressive functionalities such as prescribing light trajectories, [47] Moiré metalens for adjustable focal length, [48] dynamical wavefront modulators, [49] etc., have been demonstrated. Furthermore, the cascaded holography method allows for physical separation and combination of encoded information.…”