Switching of Photonic Crystal Lasers by Graphene.
Unique features of graphene have motivated the development of graphene-integrated photonic devices. In particular, the electrical tunability of graphene loss enables high-speed modulation of light and tuning of cavity resonances in graphene-integrated waveguides and cavities. However, efficient control of light emission such as lasing, using graphene, remains a challenge. In this work, we demonstrate on/off switching of single- and double-cavity photonic crystal lasers by electrical gating of a monolayer graphene sheet on top of photonic crystal cavities. The optical loss of graphene was controlled by varying the gate voltage Vg, with the ion gel atop the graphene sheet. First, the fundamental properties of graphene were investigated through the transmittance measurement and numerical simulations. Next, optically pumped lasing was demonstrated for a graphene-integrated single photonic crystal cavity at Vgbelow -0.6 V, exhibiting a low lasing threshold of ∼480 μW, whereas lasing was not observed at Vgabove -0.6 V owing to the intrinsic optical loss of graphene. Changing quality factor of the graphene-integrated photonic crystal cavity enables or disables the lasing operation. Moreover, in the double-cavity photonic crystal lasers with graphene, switching of individual cavities with separate graphene sheets was achieved, and these two lasing actions were controlled independently despite the close distance of ∼2.2 μm between adjacent cavities. We believe that our simple and practical approach for switching in graphene-integrated active photonic devices will pave the way toward designing high-contrast and ultracompact photonic integrated circuits.
Department of Physics, Korea University , Seoul 02842, Republic of Korea.
Min-Soo
MS
Hwang
Department of Physics, Korea University , Seoul 02842, Republic of Korea.
Ha-Reem
HR
Kim
Department of Physics, Korea University , Seoul 02842, Republic of Korea.
Kyoung-Ho
KH
Kim
Department of Physics, Korea University , Seoul 02842, Republic of Korea.
Kwang-Yong
KY
Jeong
Department of Physics, Korea University , Seoul 02842, Republic of Korea.
Jin-Sung
JS
Park
Department of Physics, Korea University , Seoul 02842, Republic of Korea.
Jae-Hyuck
JH
Choi
Department of Physics, Korea University , Seoul 02842, Republic of Korea.
Ju-Hyung
JH
Kang
Department of Physics, Korea University , Seoul 02842, Republic of Korea.|Division of Materials Science and Engineering, Hanyang University , Seoul 04763, Republic of Korea.
Jung Min
JM
Lee
Division of Materials Science and Engineering, Hanyang University , Seoul 04763, Republic of Korea.
Won Il
WI
Park
Department of Physics and Institute for the NanoCentury, KAIST , Daejeon 34141, Republic of Korea.
Jung-Hwan
JH
Song
Department of Physics and Institute for the NanoCentury, KAIST , Daejeon 34141, Republic of Korea.
Min-Kyo
MK
Seo
Department of Physics, Korea University , Seoul 02842, Republic of Korea.
Hong-Gyu
0000-0002-6375-0314
HG
Park
Graphene; nanolasers; photonic crystals; switching