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Design, Fabrication, and Experimental Characterization of Plasmonic Photoconductive Terahertz Emitters
Published on: July 8, 2013
Terahertz Bloch oscillator with a modulated bias
Timo Hyart1, Natalia V Alexeeva, Jussi Mattas
1Department of Physical Sciences, P. O. Box 3000, FI-90014 University of Oulu, Oulu, Finland.
Physical Review Letters
|April 28, 2009
Summary
Stable terahertz (THz) gain is theoretically feasible in superlattices using quasistatic microwave field modulation. This overcomes instability issues, enabling potential room-temperature THz field generation.
Area of Science:
- Solid-state physics
- Terahertz (THz) photonics
- Condensed matter physics
Background:
- Electrons in superlattices can exhibit Bloch oscillations, potentially generating THz fields.
- Achieving stable THz generation is challenging due to negative differential conductivity and electric field instability.
- Room-temperature operation is a significant goal for practical THz devices.
Purpose of the Study:
- To establish the theoretical feasibility of stable THz gain in superlattice devices.
- To overcome the instability associated with negative differential conductivity.
- To identify conditions for practical THz field generation at room temperature.
Main Methods:
- Theoretical analysis of electron dynamics in dc-biased superlattices.
- Modeling of THz gain under quasistatic microwave field modulation.
- Investigation of the role of modulation waveform harmonics.
Main Results:
- Stable THz gain is theoretically achievable in long superlattice devices.
- Quasistatic modulation of the bias field by microwave fields stabilizes the system.
- Modulation waveforms require at least two spectral harmonics for stable gain.
Conclusions:
- The proposed method theoretically enables stable THz gain in superlattices.
- Microwave field modulation offers a viable pathway for room-temperature THz oscillators.
- Further research into specific modulation waveforms is warranted for experimental realization.
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