2018/12/03 by Prasad P Iyer, Prasad P. Iyer, Mihir Pendharkar +7
Engineering · Materials Science · Physics and Astronomy · #Advanced Antenna and Metasurface Technologies #Antenna Design and Analysis #Applied Physics (physics.app-ph) #FOS: Physical sciences #Metamaterials and Metasurfaces Applications #Optics (physics.optics) #physics.app-ph #physics.optics
paper · pdf · doi:10.48550/arxiv.1903.10280
arxiv created 2018/12/03 · openalex publication_date 2018/12/03 · arxiv updated 2019/03/26 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Achieving an electrically tunable phased array optical antenna surface has been a principal challenge in the field of metasurfaces. In this letter, we demonstrate a device platform for achieving reconfigurable control over the resonant wavelength of a subwavelength optical antenna through free-carrier injection. We engineer and grow, using molecular beam epitaxy, a heterostructure of In1-xAlxAs/InAs/AlyGa1-ySb layers designed to achieve large amplitude and phase modulation of light by maximizing the refractive index change in regions of resonant field enhancement The p-i-n layers are grown on a heavily doped n-InAs layer which forms a reflecting substrate to confine the Mie resonances within the nanowires of the index tunable layers. We outline the fabrication process developed to form such tunable metasurface elements using a four-step projection lithography process and a self-aligned vertical dry etch. We experimentally demonstrate the operation of an electrically reconfigurable optical antenna element where the resonant wavelength blue shifts by 200nm only during carrier-injection. We extrapolate the experimentally measured InAs refractive index shifts to show we can achieve nearly π phase shift in a metasurface array. This solid-state device platform enables us to contact each resonant element independently to form a truly reconfigurable Fourier optical element with the promise of arbitrary control of the electromagnetic wavefront at the subwavelength scale.