This PhD project explores the use of entangled photon sources to probe brain activity at ultra-low illumination levels, addressing a key limitation in current photonic brain imaging techniques. Conventional methods like functional near-infrared spectroscopy (fNIRS) and diffuse correlation spectroscopy rely on intense laser light, which may inadvertently modulate brain activity—a phenomenon known as photobiomodulation—thus interfering with the very signals they aim to measure.

Building on recent breakthroughs in quantum spectroscopy, where entangled photons were used to measure energy transfer in photosynthetic molecules with high precision and low light levels, this project aims to apply similar techniques to the human brain. The goals include:

• Developing quantum-enhanced fNIRS using continuous-wave (CW) lasers to generate entangled photon pairs, enabling high-precision, time-domain measurements without the need for pulsed lasers.
• Comparing classical and quantum systems to quantify and minimize photobiomodulation effects, potentially demonstrating superior accuracy in quantum approaches.
• Extending the technique to new wavelength regimes (e.g., infrared) and integrating with other modalities such as electrical or magnetic recordings for multi-modal brain sensing.

This research could revolutionize non-invasive brain imaging by enabling safer, more precise, and less intrusive measurements, with broad implications for neuroscience, cognitive science, and quantum biophotonics.