Inverse Design and 3D Printing of a Metalens on an Optical Fiber Tip for Direct Laser Lithography

Abstract

An inverse-designed metalens is proposed, designed, and fabricated on an optical fiber tip via a 3D direct laser-writing technique through two-photon polymerization. A computational inverse-design method based on an objective-first algorithm was used to design a thin circular grating-like structure to transform the parallel wavefront into a spherical wavefront at the near-infrared range. With a focal length about 8 μm at an operating wavelength of 980 nm and an optimized focal spot at the scale of 100 nm, our proposed metalens platform is suitable for two-photon direct laser lithography. We demonstrate the use of the fabricated metalens in a direct laser lithography system. The proposed platform, which combines the 3D printing technique and the computational inverse-design method, shows great promise for the fabrication and integration of multiscale and multiple photonic devices with complex functionalities.

Optical Fiber-Integrated Metasurfaces: An Emerging Platform for Multiple Optical Applications

“…This fiber metalens concept will find applications in a multitude of fields, in remote focusing, optical trapping, beam generation, and efficient light collection. In another practical application with light beam focusing, the fabricated fib grated metalens was self-adapted and was directly applied to the laser lithography for light beam routing [54]. The circular metalens, made of photoresist, has a phase defined by Equation ( 5), a focal length of 8 μm, and a near-infrared operating wav In another practical application with light beam focusing, the fabricated fiber-integrated metalens was self-adapted and was directly applied to the laser lithography system for light beam routing [54].…”

“…In another practical application with light beam focusing, the fabricated fib grated metalens was self-adapted and was directly applied to the laser lithography for light beam routing [54]. The circular metalens, made of photoresist, has a phase defined by Equation ( 5), a focal length of 8 μm, and a near-infrared operating wav In another practical application with light beam focusing, the fabricated fiber-integrated metalens was self-adapted and was directly applied to the laser lithography system for light beam routing [54]. The circular metalens, made of photoresist, has a phase profile defined by Equation ( 5), a focal length of 8 µm, and a near-infrared operating wavelength of 980 nm (See Figure 5a,b).…”

Plasmonic Metalens‐Enhanced Single‐Mode Fibers: A Pathway Toward Remote Light Focusing

“…In case of illumination with linear polarized or unpolarized light, we have both effects at the same time, which reduces the efficiency of the focusing part by another factor of 1=2, that is, to T S =8. In comparison, dielectric MSs can show larger efficiencies (e.g., > 70% [13] ) as they can be made from nonabsorbing materials and allow an operation independent of polarization. Nevertheless, plasmonic MSs have advantages in some cases, particularly if the outer medium is not air.…”

“…[5,6] The advantage of our EBL approach compared with other patterning methods is that it is a wellestablished technology within the context of nanostructure implementation, which is scalable to larger areas (i.e., bundles of many fibers), technologically flexible in terms of the actual implementation strategy, and customizable for more sophisticated material combinations.A recently introduced scheme to tailor the properties of light beams relies on metasurfaces (MSs). [7][8][9][10][11][12][13][14] These ultraflat nanoscale elements represent a promising approach to shape light fields in an unprecedented manner via managing their scattering properties. MSs are typically realized by well-established nanostructuring technologies (e.g., EBL) in combination with dry or wet etching and consist of ensembles of subwavelength scatterers with nanometer dimensions having well-controlled interelement phase relations and scattering amplitudes.…”

“…A recently introduced scheme to tailor the properties of light beams relies on metasurfaces (MSs). [7][8][9][10][11][12][13][14] These ultraflat nanoscale elements represent a promising approach to shape light fields in an unprecedented manner via managing their scattering properties. MSs are typically realized by well-established nanostructuring technologies (e.g., EBL) in combination with dry or wet etching and consist of ensembles of subwavelength scatterers with nanometer dimensions having well-controlled interelement phase relations and scattering amplitudes.…”