Fast-scanning two-photon fluorescence imaging based on a microelectromechanical systems (MEMS) two-dimensional scanning mirror
ABSTRACT Towards overcoming the size limitations of conventional two-photon fluorescence microscopy, we introduce two-photon imaging based on microelectromechanical systems (MEMS) scanners. Single crystalline silicon scanning mirrors that are 0.75 mm x 0.75 mm in size and driven in two dimensions by microfabricated vertical comb electrostatic actuators can provide optical deflection angles through a range of approximately16 degrees . Using such scanners we demonstrated two-photon microscopy and microendoscopy with fast-axis acquisition rates up to 3.52 kHz.
Full-textDOI: · Available from: Olav Solgaard, Aug 31, 2015
- SourceAvailable from: Sung-Liang Chen
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- "The recent advancement in miniaturized scanning mirrors based on microelectromechanical systems (MEMS) technology has enabled the feasibility of fabricating compact fiber-optic-based endomicroscopic probes    . In our previous work, we have successfully built an all-optical MEMS-based PAM system using miniature components and achieved imaging of microvasculatures inside a canine bladder wall . "
ABSTRACT: Imaging of the cells and microvasculature simultaneously is beneficial to the study of tumor angiogenesis and microenvironments. We designed and built a fiber-optic based photoacoustic microscopy (PAM) and confocal fluorescence microscopy (CFM) dual-modality imaging system. To explore the feasibility of this all-optical device for future endoscopic applications, a microelectromechanical systems (MEMS) scanner, a miniature objective lens, and a small size optical microring resonator as an acoustic detector were employed trying to meet the requirements of miniaturization. Both the lateral resolutions of PAM and CFM were quantified to be 8.8 μm. Axial resolutions of PAM and CFM were experimentally measured to be 19 μm and 53 μm, respectively. The experiments on ex vivo animal bladder tissues demonstrate the good performance of this system in imaging not only microvasculature but also cellular structure, suggesting that this novel imaging technique holds potential for improved diagnosis and guided treatment of bladder cancer.Photoacoustics 05/2013; 1(2):30–35. DOI:10.1016/j.pacs.2013.07.001 · 4.60 Impact Factor
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- "Despite their rather established place on the MEMS landscape, novel applications of micromirrors continue to emerge, thanks to the perpetual interest they attract from the industry and academy alike. Some of the most recent research fields actively making use of micromirrors in one form or another, include endoscopic medical imaging (optical coherence tomography , two-photon microscopy , etc), 3D optical tracking , and projection displays . The dominant trend in scanning mirrors favored small (usually smaller than 1.5 mm), but very fast devices that enable high resolution and high refresh rate operation. "
ABSTRACT: A large-aperture and large-angle MEMS-based 2D pointing mirror is presented. The device is electromagnetically actuated by a moving-magnet/stationary-coil pair and potentially suited for high power laser beam shaping and beam pointing applications, such as LIDAR. The 4×4 mm2 mirror, the radially symmetric compliant membrane, and the off-the-shelf permanent magnet are manually assembled, with the planar coil kept at a well-defined vertical distance from the permanent magnet by simple alignment pins. The mirror and the compliant membrane structures are separately microfabricated on bulk silicon and SOI wafers, respectively. The hybrid integration of microfabricated and off-the-shelf components enable low-risk/high-yield fabrication, while limiting the throughput. The device features minimum inter-axis cross coupling and good linearity and is highly immune to alignment and assembly imperfections, thanks to the robust actuation principle. All the components including the bi-axial electromagnetic actuator provide a device footprint as small as the top mirror, allowing the design to be used in compact and high-fill-factor mirror arrays. With a drive coil of 400 mA and 5.12 W drive power, the total uniaxial dc rotation exceeds ±16° (optical) for both axes with good decoupling. At maximum measured angle (biaxial 10° (mechanical)), a position stability better than 0.05° over 7 h, and a position repeatability of 0.04° over 5000 switching cycles is reported. Thermally, the simulated mirror temperature increases to 64 K above the heat sink temperature with a thermal in-flux of 1 kW m−2, under absolute vacuum.Journal of Micromechanics and Microengineering 12/2012; 23(2):025002. DOI:10.1088/0960-1317/23/2/025002 · 1.73 Impact Factor
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- "The introduction of compound gradient refractive index (GRIN) lenses as focusing optics [44, 49, 50], double-clad photonic crystal fibers [51, 52] for superior detection efficiency and mechanical flexibility, and microelectromechanical systems (MEMS) scanning mirrors [52–54] has been among the most important technological advancements towards microendoscopy. The majority of micro-lenses used in nonlinear imaging, GRIN lenses, have a typical size of 0.2–1 mm in diameter, 1–10 cm in length, and a numerical aperture of less than 0.6. "
ABSTRACT: We review multiphoton microscopy (MPM) including two-photon autofluorescence (2PAF), second harmonic generation (SHG), third harmonic generation (THG), fluorescence lifetime (FLIM), and coherent anti-Stokes Raman Scattering (CARS) with relevance to clinical applications in ophthalmology. The different imaging modalities are discussed highlighting the particular strength that each has for functional tissue imaging. MPM is compared with current clinical ophthalmological imaging techniques such as reflectance confocal microscopy, optical coherence tomography, and fluorescence imaging. In addition, we discuss the future prospects for MPM in disease detection and clinical monitoring of disease progression, understanding fundamental disease mechanisms, and real-time monitoring of drug delivery.Journal of Ophthalmology 01/2011; 2011(2090-004X):870879. DOI:10.1155/2011/870879 · 1.94 Impact Factor