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

We propose a research program that focuses on the design of a handheld, non-contact Near-Infrared Photoacoustic (ncNIRPA) imager for evaluating intracranial oxygenation level, hemorrhage, and hematoma. A multi-iteration approach is proposed for the design development of the ncNIRPA imager. Due to the likelihood of open wounds in the head, lasers are deployed in the proposed ncNIRPA to support non-contact wide-area scanning of the Warfighter’s brain tissues. Eye-safe, short-duration laser pulses of two select wavelengths will be deployed to probe the excessive build-up of hemoglobin, an indicator of hemorrhage/hematoma, while an optical speckle-tolerant continuous-wave laser vibrometer will be deployed to read out the photoacoustic signatures generated by hemoglobin (oxygenated and deoxygenated). The proposed Brimrose laser vibrometer exhibits robust performance in the presence of speckles in the laser beams which tend to fail conventional laser vibrometers by causing uncontrolled signal drop-offs. Furthermore, the Brimrose laser vibrometer compensates automatically fluctuations in the standoff distance caused by, for example, involuntary bodily movement of the medic holding the ncNIRPA during triaging. Aiding operational flexibility, Photonics Integrated Circuit (PIC) will be incorporated into the ncNIRPA for light beam transport and manipulation. Researchers with expertise in PIC device design, modeling, and analysis have joined our team to tackle technical issues associated with PIC deployment. The PIC designs will be based on the design protocols of AIM Photonics where the designed device(s) will be built in its fab facilities in the Phase II program.