Abstract-Amplitude Stabilization of a Terahertz Quantum Cascade Laser with an External Metamaterial Amplitude Modulator

B. Wei, S. J. Kindness, N. W. Almond, R. Wallis, Y. Wu, Y. Ren, P. Braeuninger-Weimer, S. Hofmann, H. E. Beere, D. A. Ritchie, and R. Degl'lnnocenti

https://www.osapublishing.org/abstract.cfm?uri=cleo_si-2018-STu4D.5&origin=search

Terahertz laser sources with stable power levels are requested for astronomical, communication and spectroscopic applications. Here we demonstrate the amplitude stabilization of a terahertz quantum cascade laser with a graphene loaded split-ring-resonator array. This integrated amplitude modulator operates at room temperature and is capable of actively modulating the quantum cascade laser power level and stabilizing the power output via a PID loop. The laser power fluctuation was reduced from 1.82% to 0.19% of the total power.

© 2018 The Author(s)

Abstract-Amplitude stabilization and active control of a terahertz quantum cascade laser with a graphene loaded split-ring-resonator array

B. Wei, N. W. Almond, S. J. Kindness,R. Degl'lnnocenti, 

https://www.researchgate.net/publication/325163880_Amplitude_stabilization_and_active_control_of_a_terahertz_quantum_cascade_laser_with_a_graphene_loaded_split-ring-resonator_array

We demonstrate the amplitude stabilization of a 2.85 THz quantum cascade laser with a graphene loaded split-ring-resonator array acting as an external amplitude modulator. The transmittance of the modulator can be actively changed by modifying the graphene conductivity via electrostatic back-gating. The modulator operates at room temperature and is capable of actively modulating the quantum cascade laser power level and thus stabilizing the power output via a proportional-integral-derivative feedback control loop. The stability was enhanced by more than 10 times through actively tuning the modulation. Furthermore, this approach can be used to externally control the laser power with a high level of stability.