- Boston Children’s Develops AI System to Enhance Medical Imaging
The Columbia research team recently demonstrated the microchip's ability to produce high contrast OCT images 0.6 millimeters deeper in human tissue.
"Previously, we've been limited, but using the technique we developed in this project, we're able to say we can make any size system on a chip," said researcher Aseema Mohanty, who co-authored an AIP Photonics article on the team’s work. "That's a big deal!"
The research has received funding from the National Institutes of Health and the U.S. Air Force.
Co-author Xingchen Ji hopes the team’s work received industry funding to develop a small handheld OCT device for deployment in healthcare environments outside of hospitals.
Important chip-scale interferometer is making the tunable delay line, which calculates how light waves interact. By tuning to different optical paths, which are like different focal lengths on a camera, it collates the interference pattern to produce a high contrast three-dimensional image.
Ji and Mohanty were able to coil a 0.4-meter Si3N4 delay line into a compact 8mm2 area and added micro-heaters to the microchip in order to optically tune the heat sensitive Si3N4.
"By using the heaters, we achieve delay without any moving parts, so providing high stability, which is important for image quality of interference-based applications," said Ji.
With the components tightly bent in a small space, the researchers found it difficult to avoid losses when changing the physical size of the optical path.
Ji previously optimized fabrication to prevent optical loss. He applied this method alongside a tapered region to accurately stitch lithographic patterns together.
The team demonstrated the tunable delay line microchip on an existing commercial OCT system, showing that deeper depths could be probed while maintaining high-resolution images.
