Figures (4). Fig. 1. Fig. 2. Fig. 3. Fig. 4.Fig. 1. (A) Schematic of the 2.1 μm OCT system (BPF, bandpass filter; M, mirror; RC, reflective collimator; SL, scan lens; A, aperture; DC, dispersion compensation glass; PM, parabolic mirror; DG, diffraction grating; L, lens; LSC, line scan camera). (B) Spectra from different depths in water with the reference spectrum at 0 μm. (C) Sensitivity roll-off and (D) axial resolution versus depth with dispersion compensation (DC), co...