Rapid-scanning forward-imaging miniature endoscope for real-time optical coherence tomography

Abstract

We developed a miniature endoscope that is capable of rapid lateral scanning and is suitable for real-time forward-imaging optical coherence tomography (OCT). The endoscope has an outer diameter of 2.4 mm, consisting of a miniature tubular lead zirconate titanate (PZT) actuator, a single-mode fiber-optic cantilever, and a graded-index lens. Rapid lateral scanning at 2.8 kHz is achieved when the fiber-optic cantilever is resonated with the PZT actuator. This allows OCT imaging to be performed by fast lateral beam scanning followed by slow depth scanning, which is different from the conventional OCT imaging sequence. Real-time OCT imaging with the endoscope operated in the new image acquisition sequence at 6 frames/s is demonstrated.

An improved algorithm of structural image reconstruction with rapid scanning optical delay line for Optical Coherence Tomography

“…TDOCT couldn't provide fast acquisition speed as Fourier domain optical coherence tomography but it still can make it fast enough to make data acquisition at video rate [13]. Also images acquired with TDOCT using improved RSOD could provide information of even smallest structures which sometimes can't be visualized with some modern OCT techniques [5,8,14].…”

Resonance vibration of an optical fiber micro-cantilever using electro-thermal actuation

“…Scanning fiber endoscopy is one of the emerging areas for using fiber optics in advanced applications for bio-medical image acquisition purpose [1][2][3]. In this method, optical fiber is used as a micro-cantilever vibrating at relatively high frequencies.…”

“…Amongst potential options, use of thermal actuation through a novel technique is explored. Advantages of thermal actuation include: (1) higher forces and displacement can be achieved by applying smaller voltage; (2) there is more flexibility in material selection: thermal actuators can be manufactured from most metals; (3) generally it relies on simple principles that reduces the complexity of the system substantially (for instance there is no need for coils to induce magnetic field, or directionality of crystals for PZT).…”

A Fast, Large-Stroke Electrothermal MEMS Mirror Based on Cu/W Bimorph

“…Microelectromechanical systems (MEMS) scanning mirrors are widely used in a variety of applications such as Fourier transform (FT) spectroscopy [1,2], confocal microscopy [3], optical coherence tomography [4,5], optical switches [6], and projection displays [7]. Scan range, speed, driving voltage, power consumption and footprint are among the key parameters for MEMS scanning mirrors.…”