My background is in physics, with training in optics. For more than 30 years, my research has focused on the development and application of non-invasive optical techniques to monitor brain health and function in humans. I began working with near-infrared spectroscopy (NIRS) in the early 1990s, when the field was still emerging, and have since contributed to the development of multiple NIRS and diffuse correlation spectroscopy (DCS) instruments, as well as to the modeling and experimental validation of diffusion theory to describe light propagation in turbid media.

I am best known for my work on frequency-domain NIRS (FD-NIRS) and associated quantitative methods, including the development of the commercial ISS system, which is widely regarded as a gold standard for recovering tissue optical properties and hemoglobin oxygenation. I have also made significant contributions to the advancement of DCS technology, including combined FD-NIRS/DCS systems for bedside neuromonitoring in infants. This work has enabled quantitative measurements of cerebral blood flow, blood volume, oxygenation, and metabolism, with the goal of detecting brain compromise before irreversible injury occurs. Using these systems, I have collected data from more than 500 infants and studied normal brain development as well as the effects of clinical interventions such as therapeutic hypothermia.

In parallel, I have developed functional NIRS technologies and performed multimodal studies combining fNIRS with fMRI, MEG, and EEG to investigate neurovascular coupling and brain function in both humans and animal models. More recently, I have focused on advancing DCS sensitivity through new approaches such as time-domain DCS and interferometric camera-based DCS at 1064 nm. Over the last few years, my work has increasingly emphasized translation and accessibility, including the development of FlexNIRS, a low-cost, wearable, wireless cerebral oximeter designed for community and population health applications.