Rohin McIntosh successfully defends thesis

On August 21, Rohin McIntosh successfully defended the thesis, “Spatiospectral Control of Waves in Complex Media” (Advisor: Hui Cao).

McIntosh explained, “When waves pass through dense materials like biological tissue or clouds, they scatter randomly, scrambling the signal. Because this complex process follows consistent physical rules, we can pre-shape incoming waves so they navigate through the disorder. Using laser light, we can identify extreme pathways through these environments, enabling pulsed power delivery through and into opaque media to multiple targets at distinct times.”

McIntosh will be starting as a postdoctoral fellow in the Y-Lab at Harvard. Where he will be using spatiospectral wavefront shaping of pulsed light to study nonlinear wave physics in integrated photonics systems.

Thesis Abstract

Wave propagation through complex media such as biological tissue, multimode fibers, and clouds is dominated by multiple scattering, which scrambles an incident wave in both space and time. Yet, this random scattering process is often deterministic, allowing the interference of multiply scattered waves to be controlled by shaping the incident field. This dissertation develops a framework for shaping the spatial and spectral components of light simultaneously to enhance broadband energy delivery, recompress scattered pulses, and address multiple targets at prescribed locations and times. Experiments in two-dimensional disordered waveguides reveal how optimal scattering eigenchannels direct energy through complex media, establishing fundamental limits on energy delivery and a generalized principle of time-reversal for extended targets.