Spectroscopic measurements with dispersion encoded full range frequency domain optical coherence tomography in single- and multilayered non-scattering phantoms.

In this study, depth resolved measurements of absorption profiles in the wavelength range of 800 nm with a bandwidth of 140 nm are demonstrated using high speed spectroscopic frequency domain OCT(SOCT) and a full range reconstruction algorithm (dispersion encoded full range, DEFR). The feasibility of the algorithm for SOCT is tested in simulation and experiment. With proper calibration, SOCT with DEFR is able to extract absolute, depth resolved absorption profiles over the whole wavelength range at once without the need of tuning and performing measurements at single wavelengths sequentially. The superior acquisition speed and better phase stability in frequency domain as compared to time domain results in a better reproducibility and practicability for spectroscopic measurements. In addition, high acquisition speed in excess of 20 kHz allows to measure absorption dynamics with 50 micros time resolution, which might be useful for the investigation of pharmacokinetics or pharmacodynamics. SOCT of approximately 600 microm thick single- and multilayered, weakly scattering phantoms with varying absorption in the range of 5-80 cm(-1), equivalent to blood absorption in capillaries, is presented. SOCT measurements are compared with those using a spectrometer in transmission mode. For Indocyanine Green (ICG), a dynamic absorption measurements are demonstrated.