Distal-scanning common path probe for optical coherence tomography

In this paper, we present a distal-scanning common path probe for optical coherence tomography (OCT) equipped with a hollow ultrasonic motor and a simple and specially designed beamsplitter. This novel probe proves to be able to effectively circumvent polarization and dispersion mismatch caused by fiber motion and is more robust to a variety of interfering factors during the imaging process, experimentally compared to a conventional noncommon path probe. Furthermore, our design counteracts the attenuation of backscattering with depth and the fall-off of the signal, resulting in a more balanced signal range and greater imaging depth. Spectral-domain OCT imaging of phantom and biological tissue is also demonstrated with a sensitivity of ∼ 100 dB and a lateral resolution of ∼ 3 μm. This low-cost probe offers simplified system con- figuration and excellent robustness, and is therefore particularly suitable for clinical diagnosis as one-off medical apparatus.