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Letter
Vol. 40, No. 14 / July 15 2015 / Optics Letters
Chip-integrated nearly perfect absorber at telecom wavelengths by graphene coupled with nanobeam cavity W. XU,1 Z. H. ZHU,1,2,* K. LIU,1 J. F. ZHANG,1 X. D. YUAN,1 Q. S. LU,1
AND
S. Q. QIN1,2
1
College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073, China State Key Laboratory of High Performance Computing, National University of Defense Technology, Changsha 410073, China *Corresponding author: [email protected]
2
Received 16 April 2015; revised 10 June 2015; accepted 13 June 2015; posted 15 June 2015 (Doc. ID 238193); published 3 July 2015
We exploit the concept of critical coupling to graphene based chip-integrated applications and numerically demonstrate that a chip-integrated nearly perfect graphene absorber at wavelengths around 1.55 μm can be obtained by graphene nearly critical coupling with a nanobeam cavity. The key points are reducing the radiation loss and transmission possibly, together with controlling the coupling rate of the cavity to the input waveguide to be equal to the absorption rate of the cavity caused by graphene. Simulation results show that the absorption of monolayer graphene with a total length of only a few microns is raised up to 97%. Our study may have potential applications in chip-integrated photodetectors. © 2015 Optical Society of America
cavities [21] or to the guided resonance of a photonic crystal slab [22,23] can exhibit perfect absorption. However, these perfect absorbers are based on vertical-incidence designs, which are not suitable for chip-integrated applications. Here, we exploit the concept of critical coupling to chipintegrated applications, and propose chip-integrated perfect graphene absorber through waveguide-cavity (covered by graphene)-waveguide (WCW) system. Before discussing the specific design, we present a general theoretical description of the WCW system. Provided that the quality factor of the cavity is not too low (
Letter
Vol. 40, No. 14 / July 15 2015 / Optics Letters
Chip-integrated nearly perfect absorber at telecom wavelengths by graphene coupled with nanobeam cavity W. XU,1 Z. H. ZHU,1,2,* K. LIU,1 J. F. ZHANG,1 X. D. YUAN,1 Q. S. LU,1
AND
S. Q. QIN1,2
1
College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073, China State Key Laboratory of High Performance Computing, National University of Defense Technology, Changsha 410073, China *Corresponding author: [email protected]
2
Received 16 April 2015; revised 10 June 2015; accepted 13 June 2015; posted 15 June 2015 (Doc. ID 238193); published 3 July 2015
We exploit the concept of critical coupling to graphene based chip-integrated applications and numerically demonstrate that a chip-integrated nearly perfect graphene absorber at wavelengths around 1.55 μm can be obtained by graphene nearly critical coupling with a nanobeam cavity. The key points are reducing the radiation loss and transmission possibly, together with controlling the coupling rate of the cavity to the input waveguide to be equal to the absorption rate of the cavity caused by graphene. Simulation results show that the absorption of monolayer graphene with a total length of only a few microns is raised up to 97%. Our study may have potential applications in chip-integrated photodetectors. © 2015 Optical Society of America
cavities [21] or to the guided resonance of a photonic crystal slab [22,23] can exhibit perfect absorption. However, these perfect absorbers are based on vertical-incidence designs, which are not suitable for chip-integrated applications. Here, we exploit the concept of critical coupling to chipintegrated applications, and propose chip-integrated perfect graphene absorber through waveguide-cavity (covered by graphene)-waveguide (WCW) system. Before discussing the specific design, we present a general theoretical description of the WCW system. Provided that the quality factor of the cavity is not too low (
