This contribution presents an overview of advances in scanning micromirrors based on MEMS (Micro-electro-mechanical systems) technologies to achieve beam scanning for OCT (Optical Coherence Tomography). The use of MEMS scanners for miniaturized OCT probes requires appropriate optical architectures. Their design involves a suitable actuation mechanism and an adapted imaging scheme in terms of achievable scan range, scan speed, low power consumption, and acceptable size of the OCT probe. The electrostatic, electromagnetic, and electrothermal actuation techniques are discussed here as well as the requirements that drive the design and fabrication of functional OCT probes. Each actuation mechanism is illustrated by examples of miniature OCT probes demonstrating the effectiveness of in vivo bioimaging. Finally, the design issues are discussed to permit users to select an OCT scanner that is adapted to their specific imaging needs.

This report presents the results of a study focused on the development of an integrated probe intended for endomicroscopic application. A new type of transverse scanning probe is described, which was built using Mirau micro-interferometer fabricated in MOEMS (Micro-Opto-Electro-Mechanical Systems) technology; and a 2-axis electrothermal actuator fabricated in MEMS (Micro-Electro-Mechanical Systems) technology, connected with a GRIN lens collimator and single mode fiber. Herein we present a numerical analysis and an optimization of endomicroscopic probe-scanning properties, based on Lissajous curves. The key part of the report is 2D- and 3D-imaging of phantom structures, based on polymer material and USAF-target pattern visualized with an endomicroscopy probe. The imaging was obtained by the Swept Source Optical Coherence Tomography technique (SS-OCT), working at a central wavelength λ _c = 1060 nm, a swept range Δλ = 100 nm, an A-scan rate f _a = 200 kHz, and the scanning of samples with the use of Lissajous curves.

In this paper, we present the construction and preliminary experimental results of a MOEMS fiber-based integrated probe for endoscopic optical imaging of stomach tissue using a Swept-Source Optical Coherence Tomography (SSOCT). The probe consists of a Mirau micro-interferometer, combined with a GRIN lens collimator and a micromirror scanner. We describe the building blocks of the probe, especially the monolithically integrated Mirau mirointerferometer, fabricated by wafer-level vertical stacking and anodic bonding of Si/glass components, and the electrothermal 2-axis MEMS microscanner allowing large swept angles (up to ±22°) at high frequencies (> kHz) for low driving voltages (<20 V). The results of probe characterization, performed in a designed SS-OCT system, have confirmed proper operation of the probe. The B-scan images were obtained for central wavelength of λc = 840 nm, swept range of Dλ = 60 nm and A-scan frequency of f_A= 110 kHz. The axial resolution of the probe is equal to 5.2 μm (determined by applied swept source), whereas the lateral resolution, measured by use of USAF test pattern, is 9.8 μm.

In the frame the European project VIAMOS (www.viamos.eu) we developed a microsystem based on Mirau interferometry and applied for optical coherence tomography (OCT) imaging of living tissues. The objective is to benefit from advanced MOEMS technologies, enabling a new generation of miniature and low-cost instruments using the concept of the swept-source OCT (SSOCT) microsystem based on spectrally tuned Mirau interferometry, into which a doublet of microlens matrices (4x4) and a wafer of movable reference mirrors are included, building the active Mirau interferometer.