Wearable optical coherence tomography angiography probe with extended depth of field

Significance: Optical coherence tomography (OCT) is widely utilized to investigate brain activities and disorders in anesthetized or restrained rodents. However, anesthesia can alter several physiological parameters, leading to findings that might not fully represent the true physiological state. To advance the understanding of brain function in awake and freely moving animals, the development of wearable OCT probes is crucial. Aim: We aim to address the challenge of insufficient depth of field (DOF) in wearable OCT probes for brain imaging in freely moving mice, ensuring high lateral resolution while capturing brain vasculature across varying heights. Approach: We integrated diffractive optical elements (DOEs) capable of generating beams with an extended DOF into a wearable OCT probe. This design effectively overcomes the traditional trade-off between lateral resolution and DOF, enabling the capture of detailed angiographic images in a dynamic and uncontrolled environment. Results: The enhanced wearable OCT probe achieved a lateral resolution superior to 8 μm within a 450 μm axial range. This setup allowed for high-resolution optical coherence tomography angiography (OCTA) imaging with extended DOF, making it suitable for studying brain vasculature in freely moving mice. Conclusions: The incorporation of DOEs into the wearable OCT probe represents a significant advancement in wearable biomedical imaging. This technology facilitates the acquisition of high-resolution angiographic images with an extended DOF, thus enhancing the ability to study brain function in awake and naturally behaving animals.