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Optical systems typically use galvanometers (galvos) and scanners. Galvos move, quasi-statically, from one static position to another. Scanners move in an oscillatory fashion, typically at the device resonant frequency. MEMS devices, which have many advantages and are often used in optical systems, are typically high Q devices. Moving from one position to another for a galvo or one amplitude to another for scanners, can take many periods to settle following the ring down. During these transitions, the optical system is inactive. Here, we show how precisely timed pulses can be used (in an open loop manner) to begin or end scanner motion without ring up/ring down time. The size of pulse required is found to depend on the Q of the device, and relationships are derived. The pulse can also be separated into multiple pulse spaced one period apart if pulses of the necessary size are not possible due to constraints of the physical device. For finite Q scanners, the amplitude decreases after the initial pulse due to damping. This can be eliminated by applying an excitation at the frequency of the scanner. The necessary amplitude for this excitation is derived. Finally, by combining this open loop control algorithm with an open loop control algorithm for galvo motion the device can seamlessly move between scanner and galvo functioning. These control algorithms are demonstrated using computer simulations, analytical models and a commercially available MEMS mirror (Mirrorcle Technologies, A8L2.2). [2020-0238] [ABSTRACT FROM AUTHOR]

Standard physical vapor deposition systems are large, expensive, and slow. As part of an on-going effort to build a fab-on-a-chip, we have developed a chip-scale, low cost, fast physical vapor deposition system designed to be used with atomic calligraphy or dynamic stencil lithography to direct write nanostructures. The system comprises two MEMS devices: a chip-scale thermal evaporator and a mass sensor that serves as a film thickness monitor. Here, we demonstrate the functionality of both devices by depositing Pb thin-films. The thermal evaporator was made by fabless manufacturing using the SOIMUMPs processs (MEMSCAP, inc). It turns on in 1:46 s and reaches deposition rates as high as 7.2Å s−1 with ~1 mm separation from the target. The mass sensor is a re-purposed quartz oscillator (JTX210) that is commercially available for less than one dollar. Its resolution was measured to be 2.65 fg or 7.79E-5 monolayers of Pb. [2020-0237] [ABSTRACT FROM AUTHOR]

In this paper, we discuss the use of pulse width modulation (PWM) to control analog MEMS devices. We achieve a precise linear analog control of MEMS by applying PWM signal with a frequency well above the system’s mechanical natural frequency. We first demonstrate this using a parallel plate actuator and comb-drive, and then extend the technique to control a commercial deformable mirror. Such an approach allows the system designer to replace expensive drive electronics such as the high precision DACs and high voltage, linear amplifiers with a simple on-off switch. The advancements in the electronics industry tend to make precise timing cheaper and faster; our approach exploits these long-term trends to create low-cost control circuits. We also show how PWM control can linearize the positional response of the devices, where typically the position would depend quadratically on the applied analog voltage. [ABSTRACT FROM AUTHOR]

Here, we discuss a novel, mixed mode 3D XYZ scanner built within a single foundry process. The device has a large range of motion in X, Y, and Z ($14.1~\mu \text{m}$ in X and Y and $97.9~\mu \text{m}$ in Z) and can also rotate about two axes (7.4°), making it a 5 degree of freedom scanner. Vertical actuation can be accomplished with both thermal actuators, which have a larger range of motion, and capacitive actuators, which are faster, responding fully up to 3.2 kHz. Although useful for many applications, including scanning probe microscopy, micrometer scale optical microscopy, and manipulation of biological objects, the device was designed to be a 3D scanner for spray-painting atoms upon a surface with nanoscale precision and resolution for nanofabrication. Demonstrating the ability to combine the device with other complicated MEMS systems, it is integrated with an XY scanner designed to serve as a shutter of atomic flux. The full system has 7 degrees of freedom and 12 actuation motors, and because it is built in a low cost commercial foundry with a robust and stable process, it is easy and inexpensive to fabricate multiple copies or integrate into other complicated systems, making a system of systems. [2018-0213] [ABSTRACT FROM AUTHOR]

High-aspect-ratio metallic microstructures have a variety of potential applications in sensing and actuation. However, fabrication remains a challenge. We have fabricated nickel microstructures with over 20:1 aspect ratios by electroplating patterned carbon-coated carbon-nanotube forests using a nickel chloride bath. Pulse plating allows nickel ions to diffuse into the interior of the forest during off portions of the cycle. Done properly, this solves the problem of the formation of an external crust, which otherwise blocks nickel deposition in the interior of the structures. Thus, densities of 86 ± 3% of bulk Ni for the composite structures are achieved. Cantilever structures do not yield under load, but break. Measurements of the material properties of this composite material indicate an elastic modulus of $\sim 42$ GPa and a strength of 400 MPa. We demonstrate the utility of this method with an external field magnetic actuator consisting of a proof mass and two flexures. We achieved 1-mN actuation forces. [2014-0274] [ABSTRACT FROM PUBLISHER]

The fabrication of metallic electromagnetic meta-atoms on a soft microstructured polymer scaffold using a MEMS-based stencil lithography technique is demonstrated. Using this technique, complex metasurfaces that are generally impossible to fabricate with traditional photolithographic techniques are created. By engineering the mechanical deformation of the polymer scaffold, the metasurface reflectivity in the mid-infrared can be tuned by the application of moderate strains. [ABSTRACT FROM AUTHOR]