Transmission zeros and ultrasensitive detection in complex systems

Understanding vanishing transmission in Fano resonances in quantum systems and metamaterials, and ultralow transmission in disordered media is key to elucidating optical interactions. Using analytic theory and numerical simulations, we discover the topological structure and motion under deformation of transmission zeros in the complex energy plane. We demonstrate the zeros can be controlled to create ultranarrow Lorentzian lines in spectra of transmission time and diverging rates of frequency change of transmission zeros as they converge. This suggests a new approach to ultrasensitive detection.