Piezoelectric scanning mirrors for endoscopic optical coherence tomography

Abstract

A novel piezoelectric scanning mirror design for endoscopic optical coherence tomography (OCT) is presented. OCT is an interferometric technique providing microscopic tomographic sectioning of biological samples with mm-range penetration capability in tissue and is suited for integration with endoscopes using fiber-based light delivery to the sample. The piezoelectric scanning mirror was designed to provide wide-range rapid forwarding-looking scanning of the optical beam at the distal end of a compact catheter. The optical scanner provides a large ratio of mirror aperture to device size with rectangular mirror sizes ranging from 600 µm × 840 µm to 840 µm × 1600 µm. Static angular displacements up to ±7° (mechanical angle) were demonstrated and resonance frequencies of hundreds of Hz (and up to 1–2 kHz) were measured, depending on the mirror size. The imaging capability of the piezoelectric scanner was demonstrated using a bench-top spectrometer-based Fourier-domain OCT system.