Primarily, low-coherence interferometry yields the optical length, i. e. the product of sample length or sample depth data times the complementary sample refractive index. Each quantity, refractive index as well as sample depth can be obtained from the optical length if the complement is known. In a first step presented here, we use sample dispersion data for absolute depth or thickness measurement of dispersive samples. We shall discuss the physical implications and present preliminary results.
We measured second order dispersion of glucose solution using a Michelson Low Coherent Interferometer (LCI). Three different glucose concentrations: 20mg/dl (hypoglycemia), 100mg/dl (normal level), and 500mg/dl (hyperglycemia) are investigated over the wavelength range 0.5μm to 0.85μm, and the investigation shows that different concentrations are associated with different second-order dispersions. The second-order dispersions for wavelengths from 0.55μm to 0.8μm are determined by Fourier analysis of the interferogram. This approach can be applied to measure the second-order dispersion for distinguishing the different glucose concentrations. It can be considered as a potentially noninvasive method to determine glucose concentration in human eye. A brief discussion is presented in this poster as well.