Ultrahigh-resolution optical coherence tomography at 1.15 mum using photonic crystal fiber with no zero-dispersion wavelengths.

We report a broad-band continuum light source with high power, low noise and a smooth spectrum centered at 1.15 mum for ultrahigh-resolution optical coherence tomography (OCT). The continuum is generated by self-phase modulation using a compact 1.059 mum femtosecond laser pumping a novel photonic crystal fiber, which has a convex dispersion profile with no zero dispersion wavelengths. The emission spectrum is red-shifted from the pump wavelength, ranges from 800 to 1300 nm and results in a measured axial resolution of ~2.8 mum in air. We demonstrate ultrahigh-resolution OCT imaging of biological tissue using this light source. The results suggest PCF with this type of dispersion profile is advantageous for generating SC as a light source for ultrahigh-resolution OCT.