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Spectral singularities of a potential created by two coupled microring resonators
Optics Letters
|April 16, 2019
Summary
Engineered optical systems with gain and loss exhibit unique non-Hermitian potentials. This research demonstrates tunable properties like lasing and perfect absorption in coupled microring resonators.
Area of Science:
- Photonics
- Quantum Optics
- Non-Hermitian Physics
Background:
- Coupled microring resonators offer a platform for manipulating light propagation.
- Non-Hermitian systems, characterized by gain and loss, exhibit unique spectral properties.
- Spectral singularities in non-Hermitian systems act as phase transition points.
Purpose of the Study:
- To investigate the implementation of scattering peculiarities in coupled microring resonators.
- To demonstrate the tunability of optical scatterer properties by controlling gain-loss relations.
- To explore the connection between spectral singularities and phase transitions in optical systems.
Main Methods:
- Theoretical modeling of two coupled microring resonators (one with gain, one with loss) coupled to a bus waveguide.
- Analysis of counter-propagating modes and their spectral properties.
- Investigation of spectral singularities (second and fourth order) and their role in phase transitions.
- Parameter studies to explore the system's behavior as a laser, coherent perfect absorber, or exhibiting unidirectional reflectionlessness.
Main Results:
- The coupled microring resonator system effectively creates a non-Hermitian potential for light.
- Spectral singularities were identified as critical points separating real and complex eigenvalue spectra.
- The system demonstrated tunable functionalities including lasing, coherent perfect absorption, unidirectional reflectionlessness, and time-dependent bound states.
- These diverse behaviors were observed at discrete incident radiation wavelengths.
Conclusions:
- Coupled microring resonators with engineered gain and loss provide a versatile platform for novel optical phenomena.
- Spectral singularities are crucial for understanding phase transitions in these non-Hermitian optical systems.
- The ability to tune gain-loss relations allows for the realization of multiple advanced optical functionalities within a single device structure.
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