Approaching total absorption at near infrared in a large area monolayer graphene by critical coupling

Liu, Yonghao; Chadha, Arvinder Singh; Zhao, Ding; Piper, Jessica; Jia, Yaqi; Shuai, Yichen; Menon, Laxmy; Yang, Hongjun; Ma, Zhenqiang; Fan, Shanhui; Xia, Fengnian; Zhou, Weidong

doi:10.1063/1.4901181

Cited by 111 publications

(65 citation statements)

References 31 publications

(38 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Here, we demonstrate highly sensitive, high-speed optical imaging of local electric field dynamics in solutions using graphene and a critical-coupled planar waveguide. Using a custom numerical simulation, we designed the critically-coupled waveguide amplified platform to obtain the so-called critical coupling condition 35 where the effective absorption of monolayer graphene approaches 100%. Close to the critical-coupling point, the voltage sensitivity can be enhanced by orders of magnitude.…”

Section: Design the Cage Imaging Platformmentioning

confidence: 99%

Imaging electric field dynamics with graphene optoelectronics

et al. 2016

View full text Add to dashboard Cite

The use of electric fields for signalling and control in liquids is widespread, spanning bioelectric activity in cells to electrical manipulation of microstructures in lab-on-a-chip devices. However, an appropriate tool to resolve the spatio-temporal distribution of electric fields over a large dynamic range has yet to be developed. Here we present a label-free method to image local electric fields in real time and under ambient conditions. Our technique combines the unique gate-variable optical transitions of graphene with a critically coupled planar waveguide platform that enables highly sensitive detection of local electric fields with a voltage sensitivity of a few microvolts, a spatial resolution of tens of micrometres and a frequency response over tens of kilohertz. Our imaging platform enables parallel detection of electric fields over a large field of view and can be tailored to broad applications spanning lab-on-a-chip device engineering to analysis of bioelectric phenomena.

show abstract

Section: Design the Cage Imaging Platformmentioning

confidence: 99%

Imaging electric field dynamics with graphene optoelectronics

et al. 2016

View full text Add to dashboard Cite

show abstract

“…[26][27][28][29] And complete absorptions of monolayer graphene were numerically demonstrated by using critical coupling and guided mode resonance. [30][31][32] In the experiment, total absorptions about 40% [32] and 85% [33] and graphene absorption about 77% [25] in the visible and near-infrared were measured from monolayer graphene coupled with 1D dielectric grating or 2D silicon photonic crystals on top of a back mirror. However, higher absorption is highly desirable for high-performance graphene-based optoelectronic devices, and the experimentally realization of complete absorption for monolayer graphene based structures in the optical range is still a great challenge.…”

Section: Doi: 101002/adom201600481mentioning

confidence: 99%

“…Due to the relative low Q factor of the eigen mode (Q = 95), the absorption FWHM of the structure is much broader than that of the reported structures with high Q resonant modes. [33] The designed complete absorption structure is robust, and we can control the absorption peak wavelength by changing the grating period d, while maintaining the same grating thickness and grating fill factor (w/d), as shown in Figure 3b. The eigen mode of the absorption structure shown in Figure 6a has a relative big mode area in the cross-section and has a relative low Q factor, which reduce its sensitivity to the structure parameters, and thus the absorption structure has relative big fabrication tolerances.…”

mentioning

confidence: 99%

Experimental Demonstration of Total Absorption over 99% in the Near Infrared for Monolayer‐Graphene‐Based Subwavelength Structures

Guo

Zhu

Yuan

et al. 2016

Advanced Optical Materials

105

View full text Add to dashboard Cite

CommuniCationoptical absorption in experiment for monolayer graphene based subwavelength structures in the near-infrared. Peak absorptions over 99% at wavelength around 1.5 μm with full-width at half maximum (FWHM) about 20 nm are demonstrated from mono layer graphene coupled with different subwavelength gratings on top of a back gold mirror. The experimental results are in excellent quantitative agreement with the simulation results obtained by using finite-element method, which confirm convincingly the theoretical prediction of complete optical absorption for monolayer graphene in the near-infrared range.The schematic image of the absorption structure under investigation in this work is demonstrated in Figure 1a. The structure comprises a monolayer graphene which is sandwiched between a 1D polymethy1-methacrylate (PMMA) grating and a silica layer, and a gold layer is coated in the back side of the silica layer. The absorption structure shown in Figure 1a supports several resonant modes which could be excited by outside incident waves under phase matching conditions. When the incident wave is coupled with a resonant mode, the absorption of the structure could be enhanced due to the field enhancement in the structure. And complete absorption can be obtained when the reflection wave is canceled by the emission wave of the resonant mode since the transmission of the structure is blocked by the gold layer.The monolayer graphene based absorption structures shown in Figure 1a were fabricated on a silicon substrate, and an optical image of our fabricated sample is shown in Figure 1b. The fabrication processes are listed as follows. A 4 nm chromium (Cr) layer was first deposited on a 2 cm size silicon substrate by using electron-beam evaporation, and a 200 nm gold layer was deposited on the Cr layer by using magnetron sputtering. Then, a 520 nm silica layer was deposited by plasmaenhanced chemical vapor deposition on the gold layer. And next, a 1 cm size monolayer graphene (ACS MATERIAL) was transferred on the top of the silica layer. Finally, a PMMA layer was spin coated on the substrate and grating patterns with different periods were formed in the PMMA layer by using E-beam lithography. From Figure 1b we can see that the grating patterns with different periods have different diffraction colors, and the area of the sample with graphene has a slight difference in color from that of the area without graphene. The topview scanning electron microscope (SEM) image of a fabricated pattern is shown in Figure 1c, and the white bar in the figure represents 5 μm. We measured the Raman spectrum of the monolayer graphene after the device fabrication, and compared it with the Raman spectrum of the monolayer graphene before being transferred to our sample (provided by the ACS The copyright line of this paper was changed 13 October 2016 after initial publication.This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, pr...

show abstract

“…The ability to control rates of interband [9][10][11] and intraband 12 electronic transitions via electrostatic gating, enables novel active optoelectronic devices. At optical wavelengths, the optical absorption in graphene is limited to 2.3% 10,11,13 , however for longer wavelengths (THz 12,14,15 and microwave 8 ) absorption can be increased up to 50% when the surface impedance of graphene (ZG) matches the half of the free space impedance 16 showed enhancement up to 5.5% in IR wavelengths [21][22][23] . With the help of local plasma frequency, complete optical absorption at IR frequencies has been proposed using periodically patterned doped graphene 24,25 .…”

mentioning

confidence: 99%

Observation of Gate-Tunable Coherent Perfect Absorption of Terahertz Radiation in Graphene

et al. 2016

View full text Add to dashboard Cite

Abstract:We report experimental observation of electrically-tunable coherent perfect absorption (CPA) of terahertz (THz) radiation in graphene. We develop a reflection-type tunable THz cavity formed by a large-area graphene layer, a metallic reflective electrode and an electrolytic medium in between. Ionic gating in the THz cavity allows us to tune the Fermi energy of graphene up to 1eV and to achieve critical coupling condition at 2.8 THz with absorption of 99%. With the enhanced THz absorption, we were able to measure the Fermi energy dependence of the transport scattering time of highly doped graphene. Furthermore, we demonstrate flexible active THz surfaces that yield large modulation in the THz reflectivity with low insertion losses. We anticipate that the gate-tunable CPA will lead efficient active THz optoelectronics applications.

show abstract

Approaching total absorption at near infrared in a large area monolayer graphene by critical coupling

Cited by 111 publications

References 31 publications

Imaging electric field dynamics with graphene optoelectronics

Imaging electric field dynamics with graphene optoelectronics

Experimental Demonstration of Total Absorption over 99% in the Near Infrared for Monolayer‐Graphene‐Based Subwavelength Structures

Observation of Gate-Tunable Coherent Perfect Absorption of Terahertz Radiation in Graphene

Contact Info

Product

Resources

About