Low cost, high resolution optical coherence tomography utilizing a narrowband laser diode

We developed a low cost, high resolution optical coherence tomography system utilizing a narrowband laser diode (LD), which is usually used in optical pickup for compact disc. To achieve high axial resolution even with the narrow bandwidth of the LD, we have constructed a free space interferometer including a phase-diversity detection system and a high numerical aperture (NA) objective. The axial and lateral resolution in the air was about 2.6 μm and 1 μm, respectively. The tomographic imaging of biological tissue was demonstrated, and the results showed that our OCT system enabled cellular-level imaging.