Visible light polarization-sensitive optical coherence tomography with balanced detection.

Significance: We introduce a visible-light polarization-sensitive optical coherence tomography (PS-OCT) system that operates in the spectral domain with balanced detection (BD) capability. While the BD improves the signal-to-noise ratio (SNR), the use of shorter wavelengths improves spatial resolution and birefringence sensitivity. Aim: We aim to implement a new optical design, characterize its performance, and investigate the imaging potential for biological tissues. Approach: The design utilizes a unique interferometer and a custom spectrometer that captures four highly aligned spectra with a single area/multi-line camera. Each pair of spectral lines is highly aligned, and their subtraction yields balanced detected spectra of the PS-OCT channels. The resulting channels provide multiple imaging contrasts. Results: We measured the axial resolution and quantified the BD performance within the imaging depth. We also used a variable retarder to characterize the phase retardance and optic axis orientation measurements. Imaging results demonstrate the expected improvements for biological tissue. Conclusions: We successfully implemented BD for a high-resolution visible-light PS-OCT. Improved SNR and birefringence sensitivity allow better delineation of birefringent structures in biological tissues. This opens up new opportunities in the biomedical imaging field, especially for resolving structures and fibers that exhibit birefringence.