Open physical systems exchange energy with their surrounding environment through radiation, absorption, gain, loss, and external coupling. These processes naturally lead to non-Hermitian wave physics, where eigenfrequencies, scattering spectra, and modal responses can exhibit behavior that has no direct counterpart in closed Hermitian systems. Our group studies such phenomena with a particular focus on exceptional points, coherent perfect absorber-laser states, self-dual emitter-absorber singularities, scattering zeros and poles, and other spectral singularities.

We aim to understand how these singular wave states reshape the response of electromagnetic, photonic, and acoustic systems. Near these points, small perturbations can induce strongly enhanced spectral shifts, phase variations, linewidth changes, or scattering transitions. Beyond sensitivity enhancement, spectral singularities also provide new opportunities for controlling energy flow, mode hybridization, directional response, and wave-matter interaction. By combining coupled-mode theory, scattering-matrix analysis, circuit modeling, and experimental implementations, we seek to establish non-Hermitian physics as a practical design principle for sensing, telemetry, wave control, and secure electromagnetic systems.

Sensing systems are increasingly required to detect weak signals under realistic constraints, including noise, drift, limited bandwidth, device miniaturization, and environmental fluctuations. Our group develops ultrasensitive sensing platforms that use microwave, photonic, and acoustic resonances to convert small physical, chemical, or biological perturbations into measurable spectral, temporal, or scattering signatures. These platforms include RF and microwave circuits, wireless resonant sensors, optical and photonic structures, metasurface-inspired devices, and acoustic-wave systems.

A central goal is to move beyond sensitivity alone and evaluate sensing performance in terms of signal-to-noise ratio, dynamic range, bandwidth, robustness, and system-level usability. Non-Hermitian effects, such as exceptional points and absorber-emitter singularities, are used as physical mechanisms to enhance perturbation transduction, while careful device engineering ensures that the enhanced response remains observable and stable. Applications of interest include biomedical index monitoring, extreme precision measurement, and nanometrology. In this direction, we aim to build sensing systems that combine fundamental wave physics with practical measurement capability.

Topology provides a powerful language for describing wave phenomena that remain robust against continuous deformation, disorder, and certain forms of system imperfection. In non-Hermitian systems, topology becomes even richer because eigenvalues, eigenvectors, scattering phases, zeros, poles, and complex-frequency trajectories can all carry topological information. Our group explores non-Hermitian topology across diverse wave platforms, including electromagnetic circuits, microwave resonators, photonic structures, metasurfaces, and acoustic systems.

We are particularly interested in topological features associated with exceptional points, phase winding, scattering singularities, and complex spectral surfaces. These features can govern how modes exchange identities, how spectral branches connect, and how observable responses evolve under perturbation. Unlike conventional topology in closed systems, non-Hermitian topology is deeply connected to radiation, absorption, gain, loss, and measurement channels, making it especially relevant for practical wave devices. By studying these effects across multiple platforms, we aim to uncover general principles that link topology, open-system physics, and functional device response, enabling robust sensing, wave manipulation, and information processing based on non-Hermitian wave structures.