Dual-camera spectrometer with balanced detection for enhanced retinal OCT imaging in the living mouse eye

We developed a spectral-domain optical coherence tomography (OCT) system featuring a custom dual-camera spectrometer (DCS) for balanced detection (BD) to enhance the signal-to-noise ratio in imaging. Compared to traditional single detection, the BD approach with the calibrated DCS achieves a 15.35 dB reduction in noise floor when using a supercontinuum laser. The axial resolution of the system reaches 2.9/2.2 μm in air/tissue, with a 6-dB sensitivity roll-off depth of ∼1.36 mm. In in vivo mouse retinal imaging, DCS-BD-OCT combined with temporal speckle-averaging technique can visualize highly transparent retinal ganglion cells. Additionally, for optoretinography (ORG) measurements through intensity-based approach, it successfully restored the signal dynamics obscured by noise, improving the accuracy of extracting retinal functional responses to light stimuli.