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Updated: Jul 10, 2026
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High Resolution Phonon-assisted Quasi-resonance Fluorescence Spectroscopy
Published on: June 28, 2016
Observation of Floquet rotational super-radiance
Hadiseh Nasari1, Hady Moussa1,2, Yoshiaki Kasahara1
1Photonics Initiative, Advanced Science Research Center, City University of New York, New York, NY, USA.
Nature
|July 8, 2026
Summary
Researchers demonstrate Floquet-induced rotation for ultrafast wave energy extraction. This method uses spatio-temporal modulation to access rotational regimes, enabling angular-momentum-selective wave amplification without mechanical parts.
Area of Science:
- Wave physics
- Nonlinear optics
- Metamaterials
Background:
- Time-driven systems enable wave control via spatio-temporal modulation, mimicking motion without mechanical displacement.
- Travelling-wave modulations can emulate moving media and induce effects like Doppler-induced non-reciprocity.
- Extracting energy from rotating media is theoretically predicted via rotational Doppler shifts, but experimentally challenging due to high speeds.
Purpose of the Study:
- To demonstrate Floquet-induced rotation as a method to access ultrafast rotational regimes for wave energy extraction.
- To investigate the emergence of angular-momentum bandgaps in space-time crystals at effective superluminal speeds.
- To experimentally realize and study Floquet-induced rotational super-radiance in time-modulated resonators.
Main Methods:
- Utilizing purely spatio-temporal modulation to induce Floquet rotation, achieving effective superluminal speeds.
- Analyzing the band structure of the space-time crystal to identify angular-momentum bandgaps.
- Experimentally implementing the effect in a ring network of time-modulated resonators.
Main Results:
- Observed emergence of angular-momentum bandgaps hosting parametric processes for energy extraction.
- Demonstrated angular-momentum-selective amplification of orbital waves within a specific spectral bandwidth.
- Achieved a Floquet regime of rotational super-radiance mediated by non-Hermitian and parametric dynamics.
Conclusions:
- Floquet-induced rotation provides a controllable platform for studying energy transfer from rotating media.
- The study highlights a novel method for angular-momentum-dependent wave amplification in space-time-modulated media.
- This work opens avenues for exploring exotic wave phenomena in engineered temporal and spatial structures.
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