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Graphene based all-optical spatial terahertz modulator
Qi-Ye Wen1, Wei Tian1, Qi Mao1
1State Key Laboratory of Electronic Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, P.R.China.
Scientific Reports
|December 11, 2014
Summary
We developed an all-optical terahertz modulator using graphene on germanium (GOG). This device achieves wide-band terahertz transmission modulation with high depth and speed, driven by a low-power laser.
Area of Science:
- Optoelectronics
- Materials Science
- Terahertz Technology
Background:
- Terahertz (THz) modulators are crucial for THz applications.
- Existing modulators often require complex structures or high power.
- Graphene's unique electronic properties offer potential for novel optical devices.
Purpose of the Study:
- To demonstrate an all-optical THz modulator based on single-layer graphene on germanium (GOG).
- To investigate the static and dynamic modulation characteristics of the GOG device.
- To explore the underlying physical mechanisms responsible for THz modulation.
Main Methods:
- Fabrication of a single-layer graphene on germanium (GOG) structure.
- Utilizing a 1.55 μm continuous-wave (CW) laser for optical pumping (photodoping).
- Conducting static and dynamic experiments to measure THz transmission modulation.
Main Results:
- Achieved spectrally wide-band THz transmission modulation from 0.25 to 1 THz.
- Obtained a high modulation depth of 94% with appropriate pump power.
- Measured a modulation speed of approximately 200 KHz using a 340 GHz carrier.
Conclusions:
- The GOG device functions as an effective all-optical THz modulator.
- The wide-band modulation and high performance are attributed to graphene's third-order nonlinear optical effects.
- This technology holds promise for advanced THz communication and sensing systems.
