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An optical platform is presented for examining intrinsic contrast detection strategies when imaging retinal structure usingex vivotissue. A custom microscope was developed that scans intact tissue and collects scattered light distribution at every image pixel, allowing digital masks to be applied after image collection. With this novel approach at measuring the spatial distribution of multiply scattered light, known and novel methods of detecting intrinsic cellular contrast can be explored, compared, and optimized for retinal structures of interest. 

A liquid crystal variable retarder (LCVR) enables fast, automated control of retardance that can be used as a variable waveplate in polarimetric instruments. However, precise control of the polarization state requires calibration of the LCVR. A manufacturer calibration curve is typically supplied for a single specific wavelength and temperature, but for applications under different conditions, additional calibration is needed. Calibration is typically performed with crossed polarizers to generate an intensity curve that is converted to retardance, but this method is prone to noise when retardance is close to zero. Here, we demonstrate a simple common-path Sagnac interferometer to measure retardance and provide open source software for automated generation of calibration curves for retardance as a function of wavelength and voltage. We also provide a curve fitting method and closed-form functional representation that outputs the voltage needed to achieve a desired retardance given a specified wavelength. 

Supercontinuum (SC) sources offer high illumination power from a single-mode fiber with large spectral bandwidth including the visible spectrum, which is a growing application area for optical coherence tomography (OCT). However, SC spectra suffer from pulse-to-pulse variations, increasing noise in the resulting images. By simultaneously collecting a normalization spectrum, OCT image noise can be reduced by more than half (7 dB) for single pulses without any pulse averaging using only simple optical components.