Ultrafast Q-boosting in semiconductor metasurfaces
Yang Ziwei,
Liu Mingkai,
Smirnova Daria,
Komar Andrei,
Shcherbakov Maxim,
Pertsch Thomas,
Neshev Dragomir
Affiliations
Yang Ziwei
ARC Centre of Excellence for Transformative Meta-Optical Systems (TMOS), Department of Electronics Materials Engineering, Research School of Physics, 2219Australian National University, Canberra, ACT2600, Australia
Liu Mingkai
ARC Centre of Excellence for Transformative Meta-Optical Systems (TMOS), Department of Electronics Materials Engineering, Research School of Physics, 2219Australian National University, Canberra, ACT2600, Australia
Smirnova Daria
ARC Centre of Excellence for Transformative Meta-Optical Systems (TMOS), Department of Electronics Materials Engineering, Research School of Physics, 2219Australian National University, Canberra, ACT2600, Australia
Komar Andrei
ARC Centre of Excellence for Transformative Meta-Optical Systems (TMOS), Department of Electronics Materials Engineering, Research School of Physics, 2219Australian National University, Canberra, ACT2600, Australia
Shcherbakov Maxim
Department of Electrical Engineering and Computer Science, University of California, Irvine, CA92697, USA
Pertsch Thomas
Institute of Applied Physics, Abbe Center of Photonics, Friedrich Schiller University Jena, Albert-Einstein-Straße 15, 07745Jena, Germany
Neshev Dragomir
ARC Centre of Excellence for Transformative Meta-Optical Systems (TMOS), Department of Electronics Materials Engineering, Research School of Physics, 2219Australian National University, Canberra, ACT2600, Australia
All-optical tunability of semiconductor metasurfaces offers unique opportunities for novel time-varying effects, including frequency conversion and light trapping. However, the all-optical processes often induce optical absorption that fundamentally limits the possible dynamic increase of their quality factor (Q-boosting). Here, we propose and numerically demonstrate the concept of large Q-boosting in a single-material metasurface by dynamically reducing its structural anisotropy on a femtosecond timescale. This balance is achieved by excitation with a structured pump and takes advantage of the band-filling effect in a GaAs direct-bandgap semiconductor to eliminate the free-carrier-induced loss. We show that this approach allows a dynamic boosting of the resonance quality factor over orders of magnitude, only limited by the free-carrier relaxation processes. The proposed approach offers complete dynamic control over the resonance bandwidth and opens applications in frequency conversion and light trapping.
