We show numerically that both coherent perfect absorption and transparency can be realized in a monolayer graphene. The graphene film, doped and patterned with a periodical array of holes, can support plasmonic resonances in the Mid-infrared range. Under the illumination of two counter-propagating coherent optical beams, resonant optical absorption may be tuned continuously from 99.93% to less than 0.01% by controlling their relative phase which gives a modulation contrast of 40 dB (about 30 dB for transmission). The phenomenon provides a versatile platform for manipulating the interaction between light and graphene and may serve applications in optical modulators, transducers, sensors and coherent detectors.
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http://dx.doi.org/10.1364/OE.22.012524 | DOI Listing |
Phys Rev E
November 2024
Department of Physics & Astronomy and California NanoSystems Institute, University of California, Los Angeles, California 90095, USA.
We demonstrate that in situ coherent diffractive imaging (CDI), which leverages the coherent interference between strong and weak beams to illuminate static and dynamic structures, can serve as a highly dose-efficient imaging method. At low doses, in situ CDI can achieve higher resolution than perfect lenses with the point spread function as a delta function. Both our numerical simulations and experimental results demonstrate that combining in situ CDI with ptychography can reduce the required dose by up to two orders of magnitude compared with ptychography alone.
View Article and Find Full Text PDFPLoS One
December 2024
School of Health Policy & Management, Nanjing Medical University, Nanjing, Jiangsu, China.
To face with the challenges of governance in the digital age, such as insufficient coordination between regional governments and low quality and efficiency of government services, China has proposed the Inter-provincial Government Services Policy. The policy is capable of realizing the government's ability to handle service matters for the public in different regions, thus facilitating the regional government's coordination and upgrading the level of government services. This paper collects and organizes the texts of 28 Inter-provincial Government Services policies, and uses ROSTCM6 text mining software to screen and identify the policy text content.
View Article and Find Full Text PDFNanophotonics
May 2024
Department of Materials, University of Oxford, Oxford, UK.
Fast modulation of optical signals that carry multidimensional information in the form of wavelength, phase or polarization has fueled an explosion of interest in integrated photonics. This interest however masks a significant challenge which is that independent modulation of multi-wavelength carrier signals in a single waveguide is not trivial. Such challenge is attributed to the longitudinal direction of guided-mode propagation, limiting the spatial separation and modulation of electric-field.
View Article and Find Full Text PDFNanophotonics
February 2024
Department of Physics, Kookmin University, Seoul 02707, Republic of Korea.
Coherent perfect absorption (CPA) has been studied in various fields, such as metasurface, photonics, and acoustics, because of its ability to perfectly absorb light at a specific wavelength. However, the narrow bandwidth of CPA makes its application to on-chip photonics challenging. This limitation can be overcome by using a broadband resonator.
View Article and Find Full Text PDFSmall
December 2024
Center for Advanced Materials Research, Beijing Normal University, Zhuhai, 519087, People's Republic of China.
Herein an extremely low (0.32‒0.25 WmK) and glassy temperature-dependence (300-600 K) of lattice thermal conductivity (κ) in a monoclinic KAgSe is reported.
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