Infrared and Laser Engineering, Volume. 48, Issue 1, 125001(2019)
Optically controlled graphene based terahertz modulator
A spectrally wide-band terahertz modulator based on monolayer graphene on germanium (GOG) was proposed. Utilizing a homemade THz-TDS (Terahertz-time domain spectroscopy) system, it was experimentally demonstrated that the THz modulator can be tuned by a 1 550 nm pump beam in a frequency range from 0.2 to 1.5 THz. The average transmittance of THz decreased from 40% to 22% when the pump power was increased to 250 mW, while the absorption coefficient averaged increased from 19 to 44 cm-1. The maximum modulation depth of the GOG modulator can reach as high as 62% at 0.38 THz and in a frequency range from 0.2 to 0.7 THz, the modulation depth was over 50%. Compared with bare Ge, it was proved that the modulation performance can be moderately enhanced by introducing monolayer graphene. This novel optically controlled graphene based THz modulator provides a feasible method for terahertz applications in communication and imaging.
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Dai Zijie, Yang Jing, Gong Cheng, Zhang Nan, Sun Lu, Liu Weiwei. Optically controlled graphene based terahertz modulator[J]. Infrared and Laser Engineering, 2019, 48(1): 125001
Category: THz 技术及应用
Received: Aug. 5, 2018
Accepted: Sep. 3, 2018
Published Online: Apr. 2, 2019
The Author Email: Zijie Dai (602025965@qq.com)