Publications by Year: 2021

2021
Soon Wei Daniel Lim, Maryna L Meretska, and Federico Capasso. 10/11/2021. “A High Aspect Ratio Inverse-Designed Holey Metalens.” Nano Letters, 21, 20, Pp. 8642–8649. Publisher's VersionAbstract
Free-standing nanofins or pillar meta-atoms are the most common constituent building blocks in metalenses and metasurfaces in general. Here, we present an alternative metasurface geometry based on high aspect ratio via-holes. We design and characterize metalenses comprising ultradeep via-holes in 5 μm thick free-standing silicon membranes with hole aspect ratios approaching 30:1. These metalenses focus incident infrared light into a diffraction-limited spot. Instead of shaping the metasurface optical phase profile alone, we engineer both transmitted phase and amplitude profiles simultaneously by inverse-designing the lens effective index profile. This approach improves the impedance match between the incident and transmitted waves, thereby increasing the focusing efficiency. The holey platform increases the accessible aspect ratio of optical nanostructures without sacrificing mechanical robustness. The high nanostructure aspect ratio also increases the chromatic group delay range attainable, paving the way for a generation of high aspect ratio ruggedized flat optics, including large-area broadband achromatic metalenses.
acs.nanolett.1c02612.pdf
Soon Wei Daniel Lim, Joon-Suh Park, Maryna L. Meretska, Ahmed H. Dorrah, and Federico Capasso. 7/7/2021. “Engineering phase and polarization singularity sheets.” Nature Communications, 12, 1, Pp. 4190. Publisher's VersionAbstract
Optical phase singularities are zeros of a scalar light field. The most systematically studied class of singular fields is vortices: beams with helical wavefronts and a linear (1D) singularity along the optical axis. Beyond these common and stable 1D topologies, we show that a broader family of zero-dimensional (point) and two-dimensional (sheet) singularities can be engineered. We realize sheet singularities by maximizing the field phase gradient at the desired positions. These sheets, owning to their precise alignment requirements, would otherwise only be observed in rare scenarios with high symmetry. Furthermore, by applying an analogous procedure to the full vectorial electric field, we can engineer paraxial transverse polarization singularity sheets. As validation, we experimentally realize phase and polarization singularity sheets with heart-shaped cross-sections using metasurfaces. Singularity engineering of the dark enables new degrees of freedom for light-matter interaction and can inspire similar field topologies beyond optics, from electron beams to acoustics.
2021_lim_et_al._nature_communications.pdf
Shaoliang Yu, Jinsheng Lu, Vincent Ginis, Simon Kheifets, Soon Wei Daniel Lim, Min Qiu, Tian Gu, Juejun Hu, and Federico Capasso. 3/12/2021. “On-chip optical tweezers based on freeform optics.” Optica, 8, 3, Pp. 409. Publisher's Version 2021_yu_et_al._optica.pdf
Maryna L. Meretska*, Soon Wei Daniel Lim*, and Federico Capasso. 2021. “A high aspect-ratio holey metalens.” In CLEO 2021, Pp. SM4I.4. Publisher's Version
Maryna L. Meretska*, Soon Wei Daniel Lim*, and Federico Capasso. 2021. “Monolithic focusing metasurfaces.” In SPIE OPTO 2021, Pp. 1169509. Publisher's Version
Jinsheng Lu, Shaoliang Yu, Vincent Ginis, Simon Kheifets, Soon Wei Daniel Lim, Min Qiu, Tian Gu, Juejun Hu, and Federico Capasso. 2021. “On-chip optical tweezers based on free-form optics.” In SPIE Nanoscience+Engineering 2021, Pp. 117981O. Publisher's Version
Jinsheng Lu, Shaoliang Yu, Vincent Ginis, Simon Kheifets, Soon Wei Daniel Lim, Min Qiu, Tian Gu, Juejun Hu, and Federico Capasso. 2021. “On-Chip Optical Tweezers Based on Micro-Reflectors.” In CLEO 2021, Pp. SW3B.1. Publisher's Version
Soon Wei Daniel Lim, Joon-Suh Park, Maryna L. Meretska, Ahmed H. Dorrah, and Federico Capasso. 2021. “Singularity engineering: sculpting the dark.” In SPIE OPTO 2021, Pp. 1168018. Publisher's Version
Soon Wei Daniel Lim, Joon-Suh Park, Maryna L. Meretska, Ahmed H. Dorrah, and Federico Capasso. 2021. “Structuring phase and polarization singularity sheets in 2D.” In CLEO 2021, Pp. FW4G.5. Publisher's Version