Related Experiment Video
Updated: Jan 16, 2026
13:44
Simulation, Fabrication and Characterization of THz Metamaterial Absorbers
Published on: December 27, 2012
15.9K
Terahertz graphene-based tunable capacitance metamaterials with ultra-high amplitude modulation depth
1State Key Laboratory of Terahertz and Millimeter Waves, Department of Electrical Engineering, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China.
Light, Science & Applications
|October 1, 2025
Summary
Researchers developed a novel terahertz amplitude modulator using graphene-based tunable capacitors. This solid-state device achieves over 40 dB modulation at 2 THz with 30 MHz speed for advanced terahertz applications.
Area of Science:
- Optics and Photonics
- Materials Science
- Electrical Engineering
Background:
- Terahertz (THz) technology requires efficient amplitude modulators for applications like communications and imaging.
- Existing THz modulators often face limitations in speed, dynamic range, or operating conditions.
Purpose of the Study:
- To demonstrate a high-performance, solid-state terahertz amplitude modulator.
- To develop a scalable and practical platform for terahertz signal manipulation.
Main Methods:
- Integration of monolayer graphene as nanoscale tunable lateral capacitors within metasurface unit cells.
- Utilizing substrate-side, phase-cancelling reflection for modulation.
- Room-temperature, solid-state operation.
Main Results:
- Achieved terahertz amplitude modulation exceeding 40 dB at approximately 2 THz.
- Demonstrated a reconfiguration speed of 30 MHz.
- Verified performance under solid-state, room-temperature conditions.
Conclusions:
- The developed graphene-based metasurface offers a scalable and practical solution for terahertz amplitude modulation.
- This technology enables high-speed, large-dynamic-range terahertz communications.
- Potential applications include real-time imaging and programmable photonic circuits.
Related Concept Videos
01:25MOS Capacitor
1.5K
A Metal-Oxide-Semiconductor (MOS) capacitor is a fundamental structure used extensively in semiconductor device technology, particularly in the fabrication of integrated circuits and MOSFETs (metal-oxide-semiconductor field-effect transistors). The MOS capacitor consists of three layers: a metal gate, a dielectric oxide, and a semiconductor substrate.
The metal gate is typically made from highly conductive materials such as aluminum or polysilicon. Beneath the metal gate lies a thin layer of...
The metal gate is typically made from highly conductive materials such as aluminum or polysilicon. Beneath the metal gate lies a thin layer of...
1.5K
01:20Design Example: Capacitance Multiplier Circuit
1.5K
In integrated circuit technology, a capacitance multiplier is often utilized to produce a larger capacitance value when a small physical capacitance falls short. This is achieved by a circuit that multiplies capacitance values by a factor of up to 1000, such that a 10-pF capacitor can replicate the performance of a 100-nF capacitor.
The circuit illustrated in Figure 1 below incorporates two op-amps, with the first operating as a voltage follower and the second acting as an inverting amplifier.
The circuit illustrated in Figure 1 below incorporates two op-amps, with the first operating as a voltage follower and the second acting as an inverting amplifier.
1.5K
01:19Equivalent Capacitance
2.1K
Multiple capacitors can be connected in a circuit in series or parallel configuration. When the capacitor combination is connected to a battery, the potential drop across each capacitor and the magnitude of charge stored in the individual capacitor depends on the type of the connection. The capacitor combination is replaced by a single equivalent capacitor that stores the same amount of charge as the combination for a given potential difference.
The following strategies are adopted to calculate...
The following strategies are adopted to calculate...
2.1K
01:19Equivalent Capacitance
672
From the study of resistive circuits, it is understood that employing a series-parallel combination serves as an effective strategy for simplifying circuits. Capacitors can be arranged within a circuit in one of two ways: a series configuration or a parallel configuration. The way these capacitors are connected to a battery will influence both the potential drop across each individual capacitor and the size of the charge that each capacitor can store. This is determined by the specific type of...
672