An endoscopic forward-viewing OCT imaging probe based on a two-axis scanning mems mirror

Abstract

A two-axis scanning MEMS based forward-viewing endoscopic imaging probe has been developed and successfully applied in a swept source OCT system for three-dimensional imaging. The 2-axis MEMS mirror has an aperture size of 0.85 mm by 0.85 mm and a chip size of 1.5 mm by 1.7 mm and the outer diameter of the probe is 5.0 mm. The MEMS mirror achieves large optical scan angle up to 30 at 3 V. The MEMS based forward-imaging probe demonstrates real time 3D OCT images of human nail and rat skin with 10.6 μm axial resolution and 17.5 μm lateral resolution at a frame rate of 50 fps.

Microscanners for optical endomicroscopic applications

“…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. An electrostatic force between suspending and fixed electrodes induces the electrostatic actuation, which allows a high scanning resonant frequency but it often requires high operational voltages.…”

“…c Forward-viewing OCT imaging probe using a MEMS mirror. OCT image of human nail is obtained [39]. d Electrostatic MEMS lens scanner.…”

“…The microlens scanner is driven by an external AC magnetic field, eliminating chip circuitry, and thermal deformation induced by Joule heating. Duan et al have demonstrated an electrothermal MEMS actuator for a forward-looking OCT imaging endomicroscope [39]. The probe comprises a fiber-GRIN lens-prism module, a two-axis MEMS mirror whose size is 0.85 mm × 0.85 mm with flexible PCB, stainless-steel mount, a glass window, and an encapsulation tube.…”

Electrothermal MEMS fiber scanner for optical endomicroscopy

“…Unlike conventional excisional biopsy, optical biopsy can offer noninvasive and on-demand approach to inspect suspected lesions in real time with high resolution and further to minimize a false negative margin during tumor resection. Optical endomicroscope can be mainly achieved by employing assorted laser scanning microscopy such as optical coherence tomography [2,4], confocal [5], photo acoustic [6], or multi-photon [7] microscopy. Recently, microelectromechanical system (MEMS) driven microscanners have accelerated the size reduction of endomicroscopic catheters by using compact, high speed, low operational voltage, and low cost MEMS scanners.…”

“…Needle probe [8], MEMS mirrors [9,10], or tethered capsule catheter [11] can also serve as a side-viewing catheter. Instead, the forward-viewing catheters are based on MEMS mirrors [4,12], lens scanner [13], or fiber scanners [5,7,[14][15][16][17], which provide the same viewing direction as conventional endoscopic cameras. In particular, the resonant fiber scanner allows high scanning amplitudes at low operating voltages.…”