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Sensing with Exceptional Surfaces in Order to Combine Sensitivity with Robustness
Q Zhong1, J Ren2, M Khajavikhan2
1Department of Physics and Henes Center for Quantum Phenomena, Michigan Technological University, Houghton, Michigan 49931, USA.
Physical Review Letters
|May 4, 2019
Summary
Researchers developed robust photonic exceptional points (EPs) for advanced sensors. This new design uses an exceptional surface (ES) to maintain sensitivity while tolerating perturbations, overcoming limitations of isolated EPs.
Area of Science:
- Non-Hermitian physics
- Photonics
- Sensor technology
Background:
- Exceptional points (EPs) are singularities in non-Hermitian systems, offering high sensitivity for optical sensors.
- Isolated EPs are highly sensitive to perturbations, limiting practical applications due to fabrication errors and experimental uncertainties.
Purpose of the Study:
- To introduce a novel design concept for photonic exceptional points (EPs) that enhances robustness against perturbations while retaining sensitivity.
- To overcome the limitations of isolated EPs in practical sensor applications.
Main Methods:
- Implementation of a photonic structure featuring a hypersurface of Jordan exceptional points (EPs) embedded in a larger space.
- Analysis of system behavior under various perturbations, including undesired shifts and backscattering.
Main Results:
- A large class of perturbations shifts the operating point along the exceptional surface (ES), maintaining the system at another EP, thus ensuring robustness.
- Perturbations from back reflection or backscattering drive the operating point out of the ES, leading to enhanced sensitivity.
- The proposed geometry is implementable with standard photonic components.
Conclusions:
- The developed design offers a robust yet sensitive platform for photonic exceptional points (EPs).
- This approach addresses the critical challenge of sensitivity to perturbations in EP-based devices.
- The design concept is extendable to other physical platforms like microwave and acoustics.
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