Mary Lou Jepsen: Holographic Optics and Non-Invasive Brain Imaging

Mary Lou Jepsen is an engineer and executive known for her work in display and imaging systems at Google [x], Intel, and Facebook/Oculus. She is the founder of Openwater, a company developing a wearable medical imaging device intended to offer fMRI-level resolution using near-infrared light and holography.

Early Medical Diagnosis

In the mid-1990s, while Jepsen was a PhD candidate in holography and optics at Brown University, she experienced severe neurological and physical symptoms. An MRI scan, funded by a professor after she struggled with medical costs, revealed a non-cancerous tumor pressing against her pituitary gland. She underwent successful surgery to remove the tumor. This experience influenced her focus on reducing the cost of medical imaging.

One Laptop Per Child

In 2005, Jepsen co-founded the One Laptop Per Child (OLPC) initiative with Nicholas Negroponte. She served as Chief Technology Officer and chief architect of the XO-1 laptop, which aimed to provide low-cost computers to children in developing countries. She designed a dual-mode screen that functioned as a standard color LCD indoors and a high-resolution, sunlight-readable black-and-white display outdoors. This project required optimizing components for low power consumption and durability. She later led the Display Division at Google [x] and directed optics for Oculus VR at Facebook.

Openwater and Holographic Phase Conjugation

In 2016, Jepsen left Facebook to found Openwater. The company aims to create a wearable device capable of high-resolution brain imaging using silicon chips rather than superconducting magnets.

A primary technical challenge in using light for medical imaging is scattering, which blurs the image as photons pass through tissue. Openwater addresses this using holographic phase conjugation. The system uses near-infrared light, which can penetrate bone and tissue. A high-resolution CMOS sensor records a hologram of the scattered light as it exits the body. A computer then mathematically inverts the scattering pattern, focusing the light back through the tissue to specific points.

Brain-Computer Interface Applications

If successful, Openwater's technology could function as a non-invasive Brain-Computer Interface (BCI). Existing BCI technologies often require surgically implanted electrodes. Openwater’s approach aims to measure blood flow and microscopic changes in the refractive index of firing neurons non-invasively.

By 2025, Openwater had entered clinical trials, exploring applications such as detecting strokes in ambulances and guiding focused ultrasound treatments. Jepsen’s long-term objective is to enable communication for individuals with severe motor impairments and to broaden access to diagnostic imaging.