This proposal aims to develop a new generation of high-speed, low-cost, microelectromechanical systems
vertical cavity surface emitting lasers (MEMS-VCSELs) for optical coherence tomography (OCT) at multi-MHz
axial scan rates. The proposed effort involves a collaboration between Praevium Research, with expertise in
MEMS-VCSEL development, and the Massachusetts Institute of Technology (MIT), a leader in OCT system
integration and OCT imaging. These ultrahigh speed imaging systems enable new in vivo fundamental and
clinical imaging applications, at larger fields of view and finer resolutions than were previously possible. Multi-
MHz operation is particularly critical for advancing OCT in cancer studies, which require high speed for large
volume imaging of microstructure, and dense sampling for angiographic imaging (OCTA) and optical coherence
microscopy (OCM). The proposed low-cost laser will make these high performance technologies widely available
to the fundamental and clinical cancer research communities.
Praevium Research will focus on the development of the new high-speed, low-cost MEMS-VCSEL swept laser
source. MEMS-VCSELs have recently emerged as a near ideal laser for OCT. These devices offer a unique
combination of wide tuning range, high and variable tuning speed, dynamic single mode operation enabling
meter-scale imaging range, and the potential for low-cost, enabled by monolithic wafer-scale fabrication and
testing. The proposed work seeks to push MEMS-VCSEL technology to 2-5MHz axial scan rates in a monolithic
design, with multiple approaches to actuator design and packaging to optimize laser speeds, tuning range, and
sweep linearity. These efforts will significantly reduce manufacturing cost, providing the first volume-scalable,
commercially available swept source for multi-MHz OCT, to enable a 10x-40x speed improvement over existing
commercial OCT instruments at a fraction of the cost of current swept source technologies.
MIT will integrate the new light source with state of the art data acquisition and processing and with new
endoscopic probe technology to demonstrate in vivo imaging in patients with gastrointestinal pathologies. New
ultrahigh speed OCT system designs involving laser sweep multiplexing and linearization, and low latency OCT
processing and display, will be investigated for performance and feasibility. Micromotor probes, tethered
capsules, and piezoelectric scanners will be developed for compact and high-precision optical imaging. MIT will
demonstrate endoscopic applications of these technologies in pre-clinical studies, while investigating system
parameters and designs for optimized performance to establish workflow and imaging protocols for potential
future clinical applications. In an existing collaboration with the Boston Veterans Affairs Medical Center, MIT will
further demonstrate studies in patients with upper and lower gastrointestinal tract pathologies, assessing
capabilities for wide field coverage of mucosal structure and vasculature, and cellular morphology. These efforts
will motivate development in many other endoscopic, laparoscopic, or surgical applications.
