Ultrahigh-resolution spectral domain optical coherence tomography with a blue-diode-pumped Ti:sapphire laser and an axicon lens.

We present a novel, low-cost ultrahigh-resolution optical coherence tomography (OCT) system, based on a broadband blue-diode-pumped Kerr-lens mode-locked Ti:sapphire laser and an axicon lens to achieve high axial and lateral resolutions, respectively. With our spectral domain OCT system, we demonstrate a lateral resolution of < 3 µm and an axial resolution of 4.5 µm in air, corresponding to 3 µm resolution in biomedical tissue. Using this system, we present biomedical images of challenging biomedical tissues, namely highly transparent collagen hydrogel and opaque bone marrow.