Super-Achromatic Rapid Scanning Microendoscope for Ultrahigh-Resolution OCT Imaging

Microendoscope is a critical technology to enable high-resolution imaging of internal luminal organs with optical coherence tomography. This paper reports the development of an achromatic compound microlens and a rapid scanning microendoscope based on the microlens that offers an ultrahigh transverse resolution of 4 μm (and an axial resolution of 2.2 μm when using a low-coherence light source with a broad spectrum bandwidth of 150 nm). The rapid scanning endoscope is capable of ultrahigh-resolution (UHR) optical coherence tomography (OCT) imaging in real time at an imaging speed of about 1220 lateral scans/s, with the image quality comparable to a slow bench-top UHR-OCT system (~100 scans/s). The superior performance of a scanning endoscope made of a compound microlens over an endoscope made of a conventional GRIN (gradient index) lens in imaging biological tissues has also been demonstrated.