Dataset for The performance of low-coherence and confocal refractometry with reduced index contrast

Abstract

This paper looks to evaluate the performance of combined low-coherence and confocal refractometry under conditions of reduced refractive index contrast. The instrument measures the refractive index and thickness of transparent objects using a fibre-based low-coherence interferometer with a line-scan spectrometer. A sample was designed that roughly mimics the structure of the eye, consisting of a lens tube holding window pairs surrounded on either side by fluid chambers and sealed at the far end by diffuse black metallic plugs. Sucrose solutions of increasing concentrations were injected into the fluid chambers providing a linear variation in refractive index from 1.3330 to 1.4416. The instrument was used to measure both the phase and group refractive indices, np and ng, as well as the physical thickness t of the windows and the fluid in the chambers. Measurements show that the accuracy and uncertainty decrease with reduced refractive index contrast but remain better than 0.6% for sucrose concentrations of up to 60.3%, which is close to the saturation limit.