Development of Handheld, Optical Speckle-Tolerant Non-Contact Laser Near-Infrared Photoacoustic Imager with Photonics Integrated Circuit

To aid Combat Medics in caring for Warfighters suffering from blast-induced wounds, we developed in the Phase I program designs of a laser-based non-contact Near-Infrared Photoacoustic (ncNIRPA) Imager capable of assessing the likelihood of intracranial hematoma by mapping the spatial distribution of hemoglobin (oxy- and deoxy-Hb). The designed ncNIRPA imager automatically projects the interrogating laser beams to areas over the skull, thus achieving fast assessment of intracranial hematoma without medicÆs manual interventions. Thanks to the Government Program MonitorÆs insightful guidance, we achieved smartphone-like form factor for the ncNIRPA imager by replacing conventional free space optics with state-of-the-art photonic integrated circuit (PIC) for light beam transport and manipulations. We propose to conduct further refinements in ncNIRPA design, finalizing the designs for the PIC, projection/collection lens modules, and the novel PIC-integrated cascaded Mach-Zehnder Interferometers (MZIs) laser beam projector that involves no moving parts. Combined with the adoption of cellphone-like plastic lens modules for light projection and collection, the designed ncNIRPA imager can survive with higher probability the harsh battlefield environments. The designed PICs will be fabricated by AIM Photonics in New York while the facility and expertise in PIC devices of our team partner at University of Maryland Baltimore County will serve as the backstop to reduce Phase II program execution risks. Component technologies, including the PICs, will be validated as the prototype ncNIRPA is gradually built out during the Phase II program. Using the ncNIRPA prototype, human subject studies with limited number of volunteers will be conducted after IRB approval.