Drawing structured plasmonic field with on-chip metalens

Abstract

The ability to draw a structured surface plasmon polariton (SPP) field is an important step toward many new opportunities for a broad range of nanophotonic applications. Previous methods usually require complex experimental systems or holographic optimization algorithms that limit their practical applications. Here, we propose a simple method for flexible generation of structured SPP field with on-chip plasmonic metalenses. The metalens is composed of multiple plasmonic focusing nanostructures whose focal shape and position can be independently manipulated, and through their superposition, SPP fields with specially designed patterns are obtained. Based on this method, we demonstrate several structured SPP fields including S- and W-shaped SPP focal fields and tunable SPP bottle beams. This work could provide new ideas for on-chip manipulation of optical surface waves, and contribute to applications such as on-chip photonic information processing and integrated photonic circuits.

Efficiently Controlling near-Field Wavefronts via Designer Metasurfaces

“…As the result, wave controls based on metasurfaces can resolve many issues encountered by Bragg devices, such as multimode generation and quasi wavevector matching. A series of meta-devices, composed of nanoslits − or meta-atoms ,− with more sophisticated functionalities, were recently constructed to couple PWs into SWs with desired wavefronts. However, all these meta-devices still need the illuminations of PWs, which are not convenient for those application scenarios requiring direct control on in-plane SWs.…”

Achromatic on-chip focusing of graphene plasmons for spatial inversions of broadband digital optical signals

“…With the rapid development of material science and nanofabrication, many photonic functionalities based on the on-chip focusing of the SPPs supported by the graded-index waveguide structures have been realized, such as the sorting of the orbital angular momentum of light, 22,23 the manipulation of the longitudinal trajectory of the beam, 24,25 and the spatiotemporal operation of optical pulses. 26,27 Nonetheless, the on-chip focusing of the SPPs still faces a formidable challenge of the severe chromatic aberration due to the inherent strong wavelength dispersion of plasmonic materials, which limits its further applications in the multicolor manipulation and broadband operation. Furthermore, to process ultrashort on-chip optical pulse signals at the nanoscale, it is very urgent to achieve the achromatic onchip focusing of the SPPs, 28 which also enables expanding the capacity of nanoscale on-chip photonic devices.…”

“…The continued pursuit in highly integrated nanophotonic circuits has fueled the flourishing of surface plasmon polaritons (SPPs) (electromagnetic waves coupled to collective oscillations of free electrons in a conductor) 19 – 21 because they can circumvent the diffraction limit and confine light to deep subwavelength scales, enabling nanoscale optoelectronic components. With the rapid development of material science and nanofabrication, many photonic functionalities based on the on-chip focusing of the SPPs supported by the graded-index waveguide structures have been realized, such as the sorting of the orbital angular momentum of light, 22 , 23 the manipulation of the longitudinal trajectory of the beam, 24 , 25 and the spatiotemporal operation of optical pulses 26 , 27 . Nonetheless, the on-chip focusing of the SPPs still faces a formidable challenge of the severe chromatic aberration due to the inherent strong wavelength dispersion of plasmonic materials, which limits its further applications in the multicolor manipulation and broadband operation.…”