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Broadband terahertz amplification in a heterogeneous quantum cascade laser
Optics Express
|April 4, 2015
Summary
We developed a broadband terahertz amplifier using ultrafast gain switching in a quantum cascade laser. This device achieves over 500 GHz bandwidth and 21 dB amplification for terahertz pulses.
Area of Science:
- Optoelectronics
- Quantum Cascade Lasers
- Terahertz Technology
Background:
- Quantum cascade lasers (QCLs) are crucial for terahertz (THz) emission.
- Achieving broadband amplification in the THz range remains a challenge.
Purpose of the Study:
- To demonstrate a broadband THz amplifier.
- To leverage ultrafast gain switching in QCLs for enhanced bandwidth.
Main Methods:
- Fabrication of a coupled cavity metal-metal waveguide device with a heterogeneous active region.
- Utilizing ultrafast gain switching for THz amplification.
- Time-domain spectroscopy for spectral and temporal analysis.
Main Results:
- Achieved a terahertz amplification bandwidth exceeding 500 GHz.
- Reached an amplification factor of 21 dB for a THz seed pulse.
- Measured discrete emission modes between 2.14 and 2.68 THz in the amplified pulse train.
Conclusions:
- Ultrafast gain switching in QCLs enables broadband THz amplification.
- The demonstrated device shows significant potential for THz applications requiring wide bandwidth and high gain.
