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Published on: August 5, 2013
Microwave Vortex Beam Lasing via Photonic Time Crystals
Lei Huang1, Weixuan Zhang1, Deyuan Zou1
1Beijing Institute of Technology, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurements of Ministry of Education, Beijing Key Laboratory of Nanophotonics and Ultrafine Optoelectronic Systems, School of Physics, 100081 Beijing, China.
Researchers demonstrate surface-emitted microwave vortex beams using ring-shaped photonic time crystals (PTCs). This breakthrough enables orbital angular momentum (OAM) lasing without gain media, paving the way for advanced wireless communications and sensing.
Area of Science:
- Physics
- Electromagnetism
- Materials Science
Background:
- Microwave lasing with orbital angular momentum (OAM) is crucial for high-capacity communications and sensing.
- Conventional masers cannot produce OAM emission, and existing photonic time crystals (PTCs) lack surface-emitting capabilities for OAM modulation.
- Previous PTC designs used bulk structures, hindering surface emission and OAM control.
Purpose of the Study:
- To experimentally demonstrate surface-emitted microwave vortex beam lasing using ring-shaped PTCs.
- To achieve OAM lasing without requiring a gain medium or high-Q cavity.
- To overcome limitations of conventional masers and PTCs for OAM generation.
Main Methods:
- Developed a multiplier-driven time-varying metamaterial with over 100% equivalent permittivity modulation depth.
- Established momentum band gaps (k gaps) with sufficient bandwidth to enable self-sustained coherent microwave amplification.
- Utilized space-time modulation in circularly symmetric PTCs to induce nonreciprocity for selective OAM mode generation.
Main Results:
- Achieved the first experimental demonstration of surface-emitted microwave vortex beam lasing.
- Enabled resonance-free lasing without gain media or high-Q cavities.
- Successfully generated microwave lasing carrying OAM through induced nonreciprocity in ring-shaped PTCs.
Conclusions:
- This work bridges PTC physics with coherent OAM-carrying microwave emission.
- Established a transformative platform for next-generation wireless communications, advanced sensing, and OAM-based technologies.
- Demonstrated a novel approach to generating OAM vortex beams from surface-emitted microwave sources.
