Active manipulation of the optical spectral memory effect via scattering eigenchannels

The spectral memory effect in scattering media is crucial for applications that employ broadband illumination, as it dictates the available spectral range from independent scattering responses. Previous studies mainly considered a passive result with the average impact of the scattering medium, whereas it is vital to actively enhance or suppress this effect for applications concerned with large spectral range or fine resolution. We construct an analytical model by integrating the concepts of wave-based interference and photon-based propagation, which manifests a potential physical image for active manipulation by utilizing scattering eigenchannels. Our theoretical predictions indicate that the spectral memory effect is enhanced using high-transmission eigenchannels while it is suppressed using low-transmission eigenchannels. These predictions are supported by finite-difference time-domain simulations and experiments, demonstrating that the spectral memory effect’s range can be actively manipulated. Quantitatively, the experiments achieved variations in enhancement and suppression that exceeded threefold (∼3.27). We clarify the underlying principles of the spectral memory effect in scattering media and demonstrate active manipulation of multispectral scattering processes.