Wibool Piyawattanametha

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—This paper reports on a novel tunable capacitor with electrostatic angular vertical comb-drive (AVC) actuators. The AVC tunable capacitor creates a large offset in comb fingers through a small rotation angle—an advantage not found in conventional lateral comb-drive devices. High capacitance and large continuous tuning ratio is achieved in a compact device(More)
Optical fibers guide light between separate locations and enable new types of fluorescence imaging. Fiber-optic fluorescence imaging systems include portable handheld microscopes, flexible endoscopes well suited for imaging within hollow tissue cavities and microendoscopes that allow minimally invasive high-resolution imaging deep within tissue. A challenge(More)
Recent advances in optical imaging have led to the development of miniature microscopes that can be brought to the patient for visualizing tissue structures in vivo. These devices have the potential to revolutionize health care by replacing tissue biopsy with in vivo pathology. One of the primary limitations of these microscopes, however, is that the(More)
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(More)
Ultrahigh resolution two and three-dimensional optical coherence tomography (OCT) imaging was performed using a miniaturized, two-axis scanning catheter based upon microelectromechanical systems (MEMS) mirror technology. The catheter incorporated a custom-designed and fabricated, 1-mm diameter MEMS mirror driven by angular vertical comb (AVC) actuators on(More)
We present a two-photon microscope that is approximately 2.9 g in mass and 2.0 x 1.9 x 1.1 cm(3) in size and based on a microelectromechanical systems (MEMS) laser-scanning mirror. The microscope has a focusing motor and a micro-optical assembly composed of four gradient refractive index lenses and a dichroic microprism. Fluorescence is captured without the(More)
—In this paper, we present the design, fabrication, and measurements of a two-dimensional (2-D) optical scanner with electrostatic angular vertical comb (AVC) actuators. The scanner is realized by combining a foundry-based surface-mi-cromachining process (MultiUser MEMS Processes—MUMPs) with a three-mask deep-reactive ion-etching (DRIE) postfabri-cation(More)
DEVICE DESIGN We present the design, fabrication, and demonstration of a fully decoupled 2D gimbal scanner with angular vertical comb (AVC) actuators. The device is realized by combining a foundry surface-micromachining process (MUMPs) with a 3-mask deep-reactive-ion-etching (DRIE) post process. Surface-micromachining provides versatile mechanical design(More)
—This paper presents an effective method of linearizing the electrostatic transfer characteristics of micromachined two–di-mensional (2-D) scanners. The orthogonal scan angles of surface micromachined polysilicon scanner are controlled by using quadrant electrodes for electrostatic actuation. By using a pair of differential voltages over a bias voltage, we(More)
MEMS sensors, actuators, and subsystems can enable an important reduction in the size and mass of spacecrafts, first by replacing larger and heavier components, then by replacing entire subsystems, and finally by enabling the microfabrication of highly integrated picosats. Very small satellites (1 to 100 kg) stand to benefit the most from MEMS technologies.(More)