Tuning of Graphene-Based Optical Devices Operating in the Near-Infrared (original) (raw)
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Graphene optoelectronics from the visible to the mid-infrared
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Since its discovery in 2004, graphene, a one-atom-thick layer of carbon atoms arranged in a hexagonal lattice, has attracted huge interest from the scientific community due to its extraordinary electronic, mechanical, and optical properties. While most of the earliest studies focused on electronic transport, in recent years the fields of graphene photonics and optoelectronics have thriven. The goal of this thesis is to explore the use of graphene for novel optoelectronic devices, adopting different approaches to enhance the electrically tunable graphene-light interaction in a broad spectral range, from the visible to the mid-infrared. This includes investigating the sub-wavelength interaction and energy transfer between a dipole and a graphene sheet, as well as working on efficient photodetection schemes. Indeed graphene high electronic mobility, broadband absorption, flexibility and tunable optoelectronic properties (described in Chapter 1) make it extremely appealing for the devel...
arXiv (Cornell University), 2021
We present a proof of concept for a spectrally selective near-infrared (NIR) and short-wavelength infrared (SWIR) photodetector based on nanopatterned multilayer graphene intercalated with FeCl3 (NPMLG-FeCl3), enabling large modulation p-doping of graphene. The localized surface plasmons (LSPs) on the graphene sheets in NPMLG-FeCl3 allow for electrostatic tuning of the photodetection in the NIR and SWIR regimes from λ = 1.3 µm to 3 µm, which is out of range for nanopatterned monolayer graphene (NPG). Most importantly, the LSPs along with an optical cavity increase the absorbance from about N × 2.6% for N-layer graphene-FeCl3 (without patterning) to nearly 100% for NPMLG-FeCl3, where the strong absorbance occurs locally inside the graphene sheets only. Our NIR and SWIR detection scheme relies on the photo-thermoelectric effect induced by asymmetric patterning of the multi-layer graphene (MLG) sheets. The LSPs on the nanopatterned side create hot carriers that give rise to Seebeck photodetection at room temperature achieving a responsivity of R = 6.15 × 10 3 V/W, a detectivity of D * = 2.3 × 10 9 Jones, and an ultrafast response time of the order of 100 ns. Our theoretical results pave the way to graphene-based photodetection, optical IR communication, IR color displays, and IR spectroscopy in the NIR, SWIR, mid-wavelength infrared (MWIR), and long-wavelength infrared (LWIR) regimes.
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2009 International Symposium on Optomechatronic Technologies, 2009
We present the conductometric behavior of a single atomic carbon nanostructure (graphene) that could be promising to infrared optoelectronic applications. A graphene nanomanipulation system with focused infrared laser source for optoelectronic property characterizations is implemented. The feasibility of mechanical and electrical probing manipulations on two-dimensional thin film nanostructures is studied. Using this system, we revealed the infrared optoelectronic properties of mono-and multilayer graphene. The obtained optoelectronic parameters are compared to the single-and multi-walled nanotubes. A graphene infrared sensor is prototyped by direct writing of electrodes using gold nanoink fountain-pen method and is analyzed by electrical probing. Results show that graphene could be a promising building block for thin film optoelectronic devices.
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Nature Nanotechnology, 2012
Superlattices are artificial periodic nanostructures which can control the flow of electrons 1, 2 . Their operation typically relies on the periodic modulation of the electric potential in the direction of electron wave propagation. Here we demonstrate transparent graphene superlattices which can manipulate infrared photons utilizing the collective oscillations of carriers, i.e., plasmons 3-10 of the ensemble of multiple graphene layers. The superlattice is formed by depositing alternating wafer-scale graphene sheets and thin insulating layers, followed by patterning them all together into 3-dimensional photonic-crystal-like structures. We demonstrate experimentally that the collective oscillation of Dirac fermions in such graphene superlattices is unambiguously nonclassical: compared to doping single layer graphene, distributing carriers into multiple graphene layers strongly enhances the plasmonic resonance frequency and magnitude, which is fundamentally different from that in a conventional semiconductor superlattice 5, 6, 10 .
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Optics letters, 2015
We propose a novel scheme for an electro-optic modulator based on plasmonically enhanced graphene. As opposed to previously reported designs where the switchable absorption of graphene itself was employed for modulation, here a graphene monolayer is used to actively tune the plasmonic resonance condition through the modification of interaction between optical field and an indium tin oxide (ITO) plasmonic structure. Strong plasmonic resonance in the near infrared wavelength region can be supported by accurate design of ITO structures, and tuning the graphene chemical potential through electrical gating switches on and off the ITO plasmonic resonance. This provides much increased electro-absorption efficiency as compared to systems relying only on the tunable absorption of the graphene.
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Scientific Reports, 2016
Mid-infrared spectroscopy is of great importance in many areas and its integration with thin-film technology can economically enrich the functionalities of many existing devices. In this paper we propose a graphene-based ultra-compact spectrometer (several micrometers in size) that is compatible with complementary metal-oxide-semiconductor (CMOS) processing. The proposed structure uses a monolayer graphene as a mid-infrared surface waveguide, whose optical response is spatially modulated using electric fields to form a Fabry-Pérot cavity. By varying the voltage acting on the cavity, we can control the transmitted wavelength of the spectrometer at room temperature. This design has potential applications in the graphene-silicon-based optoelectronic devices as it offers new possibilities for developing new ultra-compact spectrometers and low-cost hyperspectral imaging sensors in mid-infrared region.
Mechanism of propagating graphene plasmons excitation for tunable infrared photonic devices
Optics Express, 2018
The mechanism of propagating graphene plasmons excitation using a nano-grating and a Fabry-Pérot cavity as the optical coupling components is studied. It is demonstrated that the system could be well described within the temporal coupled mode theory using two phenomenological parameters, namely, the intrinsic loss rate and the coupling rate of a graphene plasmonic mode, and their analytical expressions are derived. It is found that the intrinsic loss rate is solely determined by the electron relaxation time of graphene, while independent of the field distributions of the modes. Such result originates from the negligible magnetic field energy of the graphene plasmonic mode. The coupling rate is governed by the optical coupling components parameters, and varies periodically with the Fabry-Pérot cavity length. By modulating the two rates, quality factors and absorption rates can be adjusted. Furthermore, it is revealed that low refractive index of the Fabry-Pérot cavity material is vital to the enlargement of tunable band, and the underlying physics is discussed. Such plasmon excitation configuration is insensitive to light incident angle and could serve as a platform for many tunable infrared photonic device, such as surface-enhanced infrared absorption spectroscopies, infrared detectors and modulators., "Gate-tuning of graphene plasmons revealed by infrared nano-imaging," Nature 487(7405), 82-85 (2012). 10.
ACS Applied Nano Materials, 2020
Confining near-infrared (NIR) and mid-infrared (MIR) radiation (1−10 μm) at the nanoscale is one of the main challenges in photonics. Thanks to the transparency of silicon in the NIR-MIR range, optoelectronic systems like electro-optical modulators have been broadly designed in this range. However, the trade-off between energy-per-bit consumption and speed still constitutes a significant bottleneck, preventing such a technology to express its full potentialities. Moreover, the harmless nature of NIR radiation makes it ideal for bio-photonic applications. In this work, we theoretically showcase a new kind of electro-optical modulators in the NIR-MIR range that optimize the trade-off between power consumption, switching speed, and light confinement, leveraging on the interplay between graphene and metamaterials. We investigate several configurations among which the one consisting in a SiO 2 /graphene hyperbolic metamaterial (HMM) outstands. The peculiar multilayered configuration of the HMM allowed one also to minimize the equivalent electrical capacitance to achieve attoJoule electro/optical modulation at about 500 MHz switching speed. This system manifests the so-called dielectric singularity, in correspondence to which an HMM lens with resolving power of λ/1660 has been designed, allowing to resolve 3 nm-wide objects placed at an interdistance of 3 nm and to overcome the diffraction limit by 3 orders of magnitude. The imaging possibilities opened by such technologies are evident especially in biophotonic applications, where the investigation of biological entities with tailored/broadband-wavelength radiation and nanometer precision is necessary. Moreover, the modulation performances demonstrated by the graphene-based HMM configure it as a promise for ultrafast and low-power opto-electronics applications.
Investigation and characterization of graphene for optical sensing
2011 11th IEEE International Conference on Nanotechnology, 2011
We report a strong electron-photon interaction in exfoliated graphene observed at room temperature. Graphene has great potential to optoelectronic applications because of its excellent optical properties. Here, we demonstrate using the graphene-based structure for infrared detection under a zero-bias operation. When infrared light is projected to graphene, the graphene is capable to generate photocurrents. Besides, the electron-hole pairs generation of the graphenebased structure is independent of the direction of the polarized infrared source, and this makes graphene suitable for optical sensing. The device structure consists of graphene contacted with a pair of metal electrodes, which were fabricated using two nanomanipulation processes: dielectrophoresis and atomic force microscopic based nano assembly.