Miniaturized precalibration-based Lissajous scanning fiber probe for high speed endoscopic optical coherence tomography.

We present a miniaturized precalibration-based forward-viewing Lissajous scanning fiber probe for high speed endoscopic optical coherence tomography (OCT). The probe is based on an asymmetric fiber cantilever driven by the piezoelectric bender to realize two-dimensional (2D) Lissajous scanning. The stability and repeatability of the Lissajous scanning trajectory of the probe is tested by a position sensitive detector (PSD)-based position calibration setup. The two orthogonal resonant frequencies of the cantilever are measured to be 167.2 and 121 Hz. A 25 µm focal spot is formed at the working distance of 5 mm by the graded-index (GRIN) lens, and the field of view of the imaging probe is around ${1.5}\;{\rm mm} \times {1.5}\;{\rm mm}$1.5mm×1.5mm. The probe is fully packaged in a hypodermic tube for endoscopic imaging. The total rigid length and outer diameter are 35 mm and 3.5 mm, respectively. The probe is incorporated in a 50 KHz swept source OCT system with the axial resolution of 14 µm, and its imaging performance is validated by the 2D en face and 3D volumetric OCT imaging of the phantom and the biological tissue.