Showing posts with label Truong Khang Nguyen. Show all posts
Showing posts with label Truong Khang Nguyen. Show all posts

Thursday, December 12, 2019

Abstract-Numerical investigation of graphene-based efficient and broadband metasurface for terahertz solar absorber


Rajendrasinh Jadeja, Shreyas Charola, Shobhit K. Patel, Juveriya Parmar, Mayurkumar Ladumor, Truong Khang Nguyen,  Vigneswaran Dhasarathan 

https://link.springer.com/article/10.1007/s10853-019-04269-y

Graphene-based efficient metasurface solar absorber is presented. Graphene monolayer sheet is integrated over silicon dioxide dielectric layer to improve the bandwidth and achieve maximum absorption in the visible region from 430 to 770 THz. Simulation results indicate that the average absorption of our graphene-based metasurface absorber is more than 84% in the visible range. The absorber C-shape metasurface top layer placed above the graphene sheet is made up of tungsten material, and bottom layer made up of tungsten material helps in absorbing incoming electromagnetic light. The resonance frequency can be tuned in a wide frequency range by changing different physical parameters of proposed absorbers design. The absorption efficiency results of the proposed design are also compared with previously published similar absorber design to show the improvement of absorption in the proposed design. The proposed design is useful for designing next-generation graphene-based sensors and photovoltaic devices. Purposed graphene-based metasurface absorber can be used as a basic building block of solar energy-harvesting photovoltaic devices.

Wednesday, October 11, 2017

Abstract-Broadband THz radiation through tapered semiconductor gratings on high-index substrate



Truong Khang Nguyen, Phuc Toan Dang, Ikmo Park, and Khai Quang Le

https://www.osapublishing.org/josab/abstract.cfm?uri=josab-34-3-583&origin=searchtapere

We numerically demonstrate an extraordinary optical transmission (EOT) through semiconductor gratings with plasmonic properties on a high-index substrate over a broad terahertz (THz) bandwidth at the plasmonic Brewster channel. The THz EOT is due to impedance matching, an inherently non-resonant mechanism, at the grating entrance and exit faces, which are periodically carved with tapered slits. The optimal grating geometry provides a transmission of over 85% over a broad 0.2–1.0 THz bandwidth at a Brewster angle of incidence of 75°. In addition, we introduce a perfect THz absorber with low-loss and metal-free properties over a broad operating bandwidth based on the plasmonic Brewster transmission concept.
© 2017 Optical Society of America