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Lasing from Doubly Degenerate Bound States in the Continuum
Xiaobo Zhou1, Zhuang Li1, Yufeng Zhou1
1Shandong Provincial Engineering and Technical Center of Light Manipulation & Shandong Provincial Key Laboratory of Optics and Photonic Devices, School of Physics and Electronics, Shandong Normal University, Jinan, Shandong 250358, People's Republic of China.
The Journal of Physical Chemistry Letters
|October 17, 2024
Summary
This study demonstrates dual-mode vortex lasing using doubly degenerate bound states in the continuum in a photonic crystal. The research achieved vortex lasing with a topological charge of -2, showcasing orthogonal polarization states.
Area of Science:
- Photonics
- Condensed Matter Physics
- Materials Science
Background:
- Bound states in the continuum (BSCs) are unique optical states with potential for lasing.
- Achieving controlled vortex lasing from BSCs remains a challenge.
Purpose of the Study:
- To report dual-mode vortex lasing with a topological charge of -2.
- To investigate lasing behavior originating from doubly degenerate bound states in the continuum.
Main Methods:
- Fabrication of a photonic crystal slab with hexagonal TiO2 nanoparticles in a hexagonal lattice.
- Truncation of the finite array to a square boundary to modify emission properties.
- Pulsed pumping and polarization- and angle-resolved spectral measurements.
Main Results:
- Observation of dual-mode vortex lasing with a topological charge of -2.
- Lasing emerged at off-Γ points due to lifted degeneracy, resulting in two closely spaced wavelength peaks.
- The two lasing peaks exhibited orthogonal polarization states and a coherence time of approximately 1.4 ps.
Conclusions:
- Dual-mode vortex lasing can be achieved by engineering doubly degenerate bound states in the continuum in photonic crystals.
- The specific patterning and boundary conditions are crucial for enabling off-Γ point lasing.
- The results highlight the potential of BSCs for generating structured light with tailored polarization properties.
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