Forward imaging OCT endoscopic catheter based on MEMS lens scanning

Abstract

This Letter reports a fully packaged microelectromechanical system (MEMS) endoscopic catheter for forward imaging optical coherence tomography (OCT). Two-dimensional optical scanning of Lissajous patterns was realized by the orthogonal movement of two commercial aspherical glass lenses laterally mounted on two resonating electrostatic MEMS microstages at low operating voltages. The MEMS lens scanner was integrated on a printed circuit board and packaged with an aluminum housing, a gradient index fiber collimator, and an objective lens. A home-built spectral-domain OCT system with 60 kHz A-line acquisition rate was combined with the endoscopic MEMS catheter. Three-dimensional images of 256×256×995 voxels were directly reconstructed by mapping the A-line datasets along the Lissajous patterns. The endoscopic catheter can provide a new direction for forward endoscopic OCT imaging.

Microscanners for optical endomicroscopic applications

“…Compared to the spiral scanning, the Lissajous scanning also shows high uniform illumination over the full scaned area. Lissajous scanners have been demonstrated by using a MEMS based lens scanner [13] and a fiber scanner [9]. The bottom image of Fig.…”

“…The endomicroscopic microscanners mainly divide into scanning mirror, a single optical fiber scanner [7,9,[14][15][16][17][18][19][20], or a lens scanner [13,[21][22][23][24]. First, the scanning MEMS mirrors are operated by using electrostatic [25][26][27][28][29][30][31], electromagnetic [22,32], or electrothermal [33][34][35][36][37][38][39] actuation.…”

“…3 Microscanners for endomicroscopy. a Electrostatic gimbaled 2D MEMS mirror [27], b Electromagnetic 1D MEMS mirror [32], c 1D single-crystalline silicon MEMS mirror [35], (reproduced by permission of the Institution of Engineering & Technology) d spiral PZT scanner [7], e Lissajous fiber scanners using MTSO [14], f Lissajous scanned electrothermal MEMS fiber scanner [15], g electromagnetic MEMS microlens scanner [21], h electrostatic MEMS lens scanner [13] between a rotation angle and an applied voltage. In particular, a simple configuration of a bimorph cantilever substantially increases the fill factor of a mirror plate.…”

“…Paired lenses on a millimeter scale are mounted on electromagnetic [21] or electrostatic [13,23] microactuators, and they serve as scanning lenses for two dimensional laser scanning. Including commercial glass lenses, a plano-convex polydimethylsiloxane (PDMS) microlenses [21] or gradientindex (GRIN) lenses [13] can serve as a scanning lens. Siu et al have demonstrated a magnetically actuated MEMS microlens scanner by employing external magnetic field for actuation (Fig.…”

“…The scanning angle shows 23° under an external magnetic flux density of 22.2 × 10 −3 Tesla. An electrostatic MEMS lens scanner has also been demonstrated by Park [13,24]. The lens scanner has two aspheric glass lenses on orthogonally resonating electrostatic MEMS microstages for Lissajous scanning pattern (Fig.…”