Generating structured light with phase helix and intensity helix using reflection-enhanced plasmonic metasurface at 2 μm

Abstract

Mid-infrared (2–20 μm) light has been attracting great attention in many areas of science and technology. Beyond the extended wavelength range from visible and near-infrared to mid-infrared, shaping spatial structures may add opportunities to grooming applications of mid-infrared photonics. Here, we design and fabricate a reflection-enhanced plasmonic metasurface and demonstrate efficient generation of structured light with the phase helix and intensity helix at 2 μm. This work includes two distinct aspects. First, structured light (phase helix, intensity helix) generation at 2 μm, which is far beyond the ability of conventional spatial light modulators, is enabled by the metasurface with sub-wavelength engineered structures. Second, the self-referenced intensity helix against environmental noise is generated without using a spatially separated light. The demonstrations may open up advanced perspectives to structured light applications at 2 μm, such as phase helix for communications and non-communications (imaging, sensing) and intensity helix for enhanced microscopy and advanced metrology.

On-chip silicon photonic signaling and processing: a review

“…Also, silicon photonics has been considered to be a powerful platform for broadband mid-infrared photonics [304,305]. Additionally, some more interesting applications, such as optical coherence tomography [306,307], ultrafast optical ranging [308], spatial mode or structured light manipulation [309][310][311][312][313][314][315][316][317][318][319], optical phased array and LiDAR [320][321][322][323][324] have also been widely studied. In future, it is believed that silicon photonics will facilitate more and more emerging advanced applications in a compact way with superior performance.…”

Generation and Detection of Structured Light: A Review

“…Integrated devices with small volumes for generating various structured light beams are, remarkably, showing a promise prospect. Here, we present different types of integrated devices for generating structured light beams based on diverse materials, including silicon [55][56][57][58][59][60], silica [61][62][63], metals [64][65][66], crystal [67], InP [68][69][70][71], and so on. Among them, the active material InP can be used to build a structured light beam laser.…”

“…In addition to silicon waveguides, metal-based metasurface can also be used to generate structured light beams. Figure 5C illustrates the structure of a reflection-enhanced plasmonic metasurface for efficient generation of structured light with the phase helix and intensity helix at 2 µm [64]. Such a plasmonic metasurface is formed by a V-shaped optical antenna array.…”

Digitized subwavelength surface structure on silicon platform for wavelength-/polarization-/charge-diverse optical vortex generation

“…Unlike ordinary light beams with a planar phasefront, the generation of optical vortices characterized by doughnut intensity pro les and helical phasefronts usually relies on bulky devices used for mode conversion, such as cylindrical lens pairs, spiral phase plates, diffractive optical elements, and spatial light modulators [41][42][43][44]. Additionally, resonator cavities, qplates, metamaterials and metasurfaces are also used for generating optical vortices [45][46][47][48][49][50][51][52]. Very recently, for the sake of miniaturization and integration, photonic integrated devices have been demonstrated to generate optical vortices [53][54][55][56][57][58][59][60][61][62][63][64][65].…”