AbstractPhotodetection in the near- and mid-infrared spectrum requires a suitable absorbing material able to meet the respective targets while ideally being cost-effective. Graphene, with its extraordinary optoelectronic properties, could provide a material basis simultaneously serving both regimes. The zero-band gap offers almost wavelength independent absorption which lead to photodetectors operating in the infrared spectrum. However, to keep noise low, a detection mechanism with fast and zero bias operation would be needed. Here, we show a self-powered graphene photodetector with a > 400 GHz frequency response. The device combines a metamaterial perfect absorber architecture with graphene, where asymmetric resonators induce photothermoelectric directional photocurrents within the graphene channel. A quasi-instantaneous response linked to the photothermoelectric effect is found. Typical drift/diffusion times optimization are not needed for a high-speed response. Our results demonstrate that these photothermoelectric directional photocurrents have the potential to outperform the bandwidth of many other graphene photodetectors and most conventional technologies.

Phototransistors are light-sensitive devices featuring a high dynamic range, low-light detection, and mechanisms to adapt to different ambient light conditions. These features are of interest for bioinspired applications such as artificial and restored vision. In this work, we report on a graphene-based phototransistor exploiting the photogating effect that features picowatt- to microwatt-level photodetection, a dynamic range covering six orders of magnitude from 7 to 10(7) lux, and a responsivity of up to 4.7 x 10(3) A/W. The proposed device offers the highest dynamic range and lowest optical power detected compared to the state of the art in interfacial photogating and further operates air stably. These results have been achieved by a combination of multiple developments. For example, by optimizing the geometry of our devices with respect to the graphene channel aspect ratio and by introducing a semitransparent top-gate electrode, we report a factor 20-30 improvement in responsivity over unoptimized reference devices. Furthermore, we use a built-in dynamic range compression based on a partial logarithmic optical power dependence in combination with control of responsivity. These features enable adaptation to changing lighting conditions and support high dynamic range operation, similar to what is known in human visual perception. The enhanced performance of our devices therefore holds potential for bioinspired applications, such as retinal implants.

Although graphene has met many of its initially predicted optoelectronic, thermal, and mechanical properties, photodetectors with large spectral bandwidths and extremely high frequency responses remain outstanding. In this work, we demonstrate a >500 gigahertz, flat-frequency response, graphene-based photodetector that operates under ambient conditions across a 200-nanometer-wide spectral band with center wavelengths adaptable from <1400 to >4200 nanometers. Our detector combines graphene with metamaterial perfect absorbers with direct illumination from a single-mode fiber, which breaks with the conventional miniaturization of photodetectors on an integrated photonic platform. This design allows for much higher optical powers while still allowing record-high bandwidths and data rates. Our results demonstrate that graphene photodetectors can outperform conventional technologies in terms of speed, bandwidth, and operation across a large spectral range.

Achieving electrically driven light sources on a silicon substrate is one of the great challenges in integrated optics. For low-power applications, one possible candidate could be Light Emitting Tunnel Junctions (LETJs) [1] . Unlike many semiconductor light sources that rely on direct-bandgap materials, the emission characteristics of LETJs are not strongly dependent on the material choice, but are determined by the electrical and optical environment of the tunnelling interface. While most electrons tunnel elastically from one electrode to the other, some can couple to and excite electromagnetic modes in a broad range of frequencies, spanning the microwave to the visible [1] – [3] .

A novel vertical incidence metamaterial enhanced graphene photodetector featuring a 200 nm spectral window and a setup limited bandwidth of 500 GHz is demonstrated. The photodetector has been tested for data transmission in an all plasmonic EOE-link offering unprecedented 250 GHz bandwidth.

Terahertz (THz) electrical signal generation from a photoactive semiconductor device illuminated by an optical pulse is modeled and simulated. Hydrodynamic equations in time domain are numerically solved for both electrons and holes using the discontinuous Galerkin time-domain finite element method (DGTD-FEM) for the high-frequency charge transport that occurs in the semiconductor device. The obtained frequency spectra of photocurrent in various semiconductor materials under illumination of an ultrashort light pulse are presented. The inertia effects and ballistic transport of carriers play an important role to determine the frequency response of these materials, and the developed hydrodynamic model (HDM) solver delivers a transport analysis by predicting higher and wideband frequency capabilities for GaAs and Ge detectors over Si-photodetectors.

Integrated photon pair generation based on spontaneous parametric down conversion (SPDC) or spontaneous four wave mixing (SFWM) promise to be a low-cost alternative to current table-top setups for the generation of entangled photons or heralded single photons [1] . Integrated devices feature smallest mode volumes. This enables higher pair-generation rates per pump-power compared to free-space components.

This corrects the article DOI: 10.1103/PhysRevLett.121.033602.

Combining reprogrammable optical networks with complementary metal-oxide semiconductor (CMOS) electronics is expected to provide a platform for technological developments in on-chip integrated optoelectronics. We demonstrate how opto-electro-mechanical effects in micrometer-scale hybrid photonic-plasmonic structures enable light switching under CMOS voltages and low optical losses (0.1 decibel). Rapid (for example, tens of nanoseconds) switching is achieved by an electrostatic, nanometer-scale perturbation of a thin, and thus low-mass, gold membrane that forms an air-gap hybrid photonic-plasmonic waveguide. Confinement of the plasmonic portion of the light to the variable-height air gap yields a strong opto-electro-mechanical effect, while photonic confinement of the rest of the light minimizes optical losses. The demonstrated hybrid architecture provides a route to develop applications for CMOS-integrated, reprogrammable optical systems such as optical neural networks for deep learning.

We demonstrate a low-loss coupling scheme between a silicon photonic waveguide and a hybrid-plasmonic waveguide. Measured coupling efficiencies reach up to 94% or -0.27 dB. The metal-insulator-semiconductor structure is fabrication-tolerant and adaptable to a wide range of materials including those used in CMOS processes. The coupler is a promising building block for low-loss active plasmonic devices.

We report on light generation via inelastic electron tunneling in a metal-oxide-semiconductor (MOS) junction, which is directly integrated within a silicon photonic waveguide. We generate an optical power of 6.8 pW. © 2019 The Author(s)

We demonstrate plasmonic-electro-mechanical-switches that feature a plasmonic resonator (Q> 1000). This enables low on/off voltages (875mV)and low insertion losses $(\sim1\text{dB})$ The performance proofs that plasmonics is competitive with photonics not only at highest speed. © 2019 The Author(s)

Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text D. Chelladurai, M. Doderer, U. Koch, Y. Fedoryshyn, C. Haffner, and J. Leuthold, "Photonic-Plasmonic Hybrid Waveguide Couplers with a 91% Efficiency," in Advanced Photonics 2018 (BGPP, IPR, NP, NOMA, Sensors, Networks, SPPCom, SOF), OSA Technical Digest (online) (Optica Publishing Group, 2018), paper IW4B.5. Export Citation BibTex Endnote (RIS) HTML Plain Text Citation alert Save article

We report on rotating an optically trapped silica nanoparticle in vacuum by transferring spin angular momentum of light to the particle's mechanical angular momentum. At sufficiently low damping, realized at pressures below 10^{-5}  mbar, we observe rotation frequencies of single 100 nm particles exceeding 1 GHz. We find that the steady-state rotation frequency scales linearly with the optical trapping power and inversely with pressure, consistent with theoretical considerations based on conservation of angular momentum. Rapidly changing the polarization of the trapping light allows us to extract the pressure-dependent response time of the particle's rotational degree of freedom.