Metasurface Polarization Optics: Independent Phase Control of Arbitrary Orthogonal States of Polarization

Mueller, J. P. Balthasar; Rubin, Noah A.; Devlin, Robert C.; Groever, Benedikt; Capasso, Federico

doi:10.1103/physrevlett.118.113901

Cited by 1,249 publications

(532 citation statements)

References 24 publications

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“…Firstly, we notice that the source-drain current is different from a typical graphene's ambipolar I-V curve relative to the Dirac point (~1.4 V), which is a sign of a strong asymmetric charge transfer in this short-channel device. It is known that the graphene sheet underneath the metal contact has a gate-uncontrollable charge density due to Fermi level pinning, which defines the hundreds of nanometers-wide charge transfer region into the channel (36,37). Thus, for long channel (W >> Lct) graphene transistor-like devices, the Fermi level pinning usually introduces a minor degraded carrier transport performance when the channel is electrostatically gated from one to the other polarity, due to the formation of p-n junctions inside the channel (Fig.…”

Section: Resultsmentioning

confidence: 99%

Compact Graphene Plasmonic Slot Photodetector on Silicon-on-Insulator with High Responsivity

Kikunaga

Wang

et al. 2020

ACS Photonics

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Graphene has extraordinary electro-optic properties and is therefore a promising candidate for monolithic photonic devices such as photodetectors. However, the integration of this atom-thin layer material with bulky photonic components usually results in a weak light-graphene interaction leading to large device lengths limiting electro-optic performance.In contrast, here we demonstrate a plasmonic slot graphene photodetector on silicon-oninsulator platform with high-responsivity given the 5 µm-short device length. We observe that the maximum photocurrent, and hence the highest responsivity, scales inversely with the slot gap width. Using a dual-lithography step, we realize 15 nm narrow slots that show a 15-times higher responsivity per unit device-length compared to photonic graphene photodetectors. Furthermore, we reveal that the back-gated electrostatics is overshadowed by channel-doping contributions induced by the contacts of this ultra-short channel graphene photodetector. This leads to quasi charge neutrality, which explains both the previously-unseen offset between the maximum photovoltaic-based photocurrent relative to graphene's Dirac point and the observed non-ambipolar transport. Such micrometer compact and absorption-efficient photodetectors allow for short-carrier pathways in nextgeneration photonic components, while being an ideal testbed to study short-channel carrier physics in graphene optoelectronics. Introduction.Graphene has become a complementary platform for electronics and optoelectronics because of its remarkable properties and versatility(1). A variety of applications exploit graphene's peculiar features to include modulators(2), plasmonic optoelectronics(3-6), photovoltaic devices (7), ultrafast lasers (8), and photo-detection(9, 10). For photo conversion applications the linear and gap-less band structure of graphene results in wavelength-independent absorption (11,12).Moreover, graphene's carrier can be tuned via electrostatically doping, thus modulating light absorption. Due to its superb carrier mobility (13,14), graphene-based absorption enables ultrafast conversion of photons or plasmons to electrical currents or voltages. However, the light-graphene interaction, and consequently the responsivity of graphene-based devices, is usually rather weak due to the geometrical mismatch between graphene's atom-thin thickness and the diffractionlimited optical mode area of photonic components.The first-generation of graphene-based free-space photodetectors (PDs) uses metal-graphenemetal structures(14); choosing different work-functions for the source-and drain contacts results in an asymmetric band structure, thus enabling non-biased band-bending for charge polarity separation, leading to near-zero dark current. Interdigitated metallic contacts, are typically adopted Corresponding AuthorVolker Sorger, sorger@gwu.edu Funding SourcesVS is funded by AFOSR (FA9550-17-1-0377) and ARO (W911NF-16-2-0194).

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Section: Resultsmentioning

confidence: 99%

Compact Graphene Plasmonic Slot Photodetector on Silicon-on-Insulator with High Responsivity

Kikunaga

Wang

et al. 2020

ACS Photonics

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“…Very recently, the geometric phase was assessed in the context of surface plasmon waves [25] and Young's double-pinhole experiment, where interfering electromagnetic fields emanating from the apertures form a spatially periodic polarization pattern [26]. The notion of Pancharatnam-Berry phase also appears extensively in connection of the so-called geometric phase metasurfaces [27][28][29].…”

Section: Introductionmentioning

confidence: 99%

Geometric phase in beating of light waves

et al. 2019

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Beating is a simple physical phenomenon known for long in the context of sound waves but remained surprisingly unexplored for light waves. When two monochromatic optical beams of different frequencies and states of polarization interfere, the polarization state of the superposition field exhibits temporal periodic variation-polarization beating. In this work, we reveal a foundational and elegant phase structure underlying such polarization beating. We show that the phase difference over a single beating period decomposes into the Pancharatnam-Berry geometric phase and a dynamical phase of which the former depends exclusively on the intensities and polarization states of the interfering beams whereas the sum of the phases is determined solely by the beam frequencies. Varying the intensity and polarization characteristics of the beams, the relative contributions of the geometric and dynamical phases can be adjusted. The geometric phase inherent in polarization beating is governed by a compact expression containing only the Stokes parameters of the interfering waves and can alternatively be obtained from the individual beam intensities and the amplitude of the intensity beats. We demonstrate both approaches experimentally by using an interferometer with a fast detector and a specific polarimetric arrangement. Polarization beating has a unique character that the geometric and dynamical phases are entangled, i.e. variation in one unavoidably leads to a change in the other. Our work expands geometric phases into a new domain and offers important novel insight into the role of polarization in interference of electromagnetic waves.

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“…One might hence envisage ultracompact and ultralight optical components acting over all the key parameters of light -amplitude, phase and polarization. What is more, the possibility to access the full T -matrix parameter space by means of a simple hole-shape tuning of a fixed-thickness membrane allows to implement space-variant metasurfaces capable of performing more advanced operations with respect to what is known to date [33], with possible applications to beam shaping, holography, and cryptography. As a final remark we highlight that the targeting procedure, which we performed at a wavelength of 1.55 µm that is of direct interest to the telecommunication technology, is fully scalable, thanks to the scale invariance of Maxwell equations.…”

Section: Inverse Problem and Metasurface Minimalitymentioning

confidence: 99%

“…For instance, a dielectric film with a non-centrosymmetric partially etched planar pattern was proposed as a simple gateway towards strong chiro-optical phenomena [28]. Nonetheless, there is a wide interest in developing subwavelength-patterned high-index dielectrics, both for applications and for fundamental research: from one side, they enable the synthesis of flat lenses, polarimeters, spectrometers, nonlinear components and computer-generated holograms [29][30][31][32][33][34]; from another side, they exhibit a variety of intriguing phenomena such as Fano lineshapes, perfect forward scattering, geometric phase effects, and bound states in the continuum resonances [35][36][37][38][39].…”

Section: Introductionmentioning

confidence: 99%

Photonic bands, superchirality, and inverse design of a chiral minimal metasurface

et al. 2019

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Photonic band structures are a typical fingerprint of periodic optical structures, and are usually observed in spectroscopic quantities such as transmission, reflection and absorption. Here we show that also the chiro-optical response of a metasurface constituted by a lattice of non-centrosymmetric, L-shaped holes in a dielectric slab shows a band structure, where intrinsic and extrinsic chirality effects are clearly recognized and connected to localized and delocalized resonances. Superchiral near-fields can be excited in correspondence to these resonances, and anomalous behaviors as a function of the incidence polarization occur. Moreover, we introduce a singular value decomposition (SVD) approach to show that the above mentioned effects are connected to specific fingerprints of the SVD spectra. Finally, we demonstrate by means of an inverse design technique that the metasurface based on an L-shaped hole array is a minimal one. Indeed, its unit cell geometry depends on the smallest number of parameters needed to implement arbitrary transmission matrices compliant with the general symmetries for 2d-chiral structures. These observations enable more powerful wave operations in a lossless photonic environment.

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Metasurface Polarization Optics: Independent Phase Control of Arbitrary Orthogonal States of Polarization

Cited by 1,249 publications

References 24 publications

Compact Graphene Plasmonic Slot Photodetector on Silicon-on-Insulator with High Responsivity

Compact Graphene Plasmonic Slot Photodetector on Silicon-on-Insulator with High Responsivity

Geometric phase in beating of light waves

Photonic bands, superchirality, and inverse design of a chiral minimal metasurface

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