&lt;title&gt;Laser Doppler vibrometry for optical MEMS&lt;/title&gt;

Lawrence, Eric M.; Speller, Kevin E.; Yu, Duli

doi:10.1117/12.468168

Cited by 11 publications

(4 citation statements)

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“…During the experiments, the measured channel of the vibrometer recorded the analog velocity output, and the reference channel recorded the voltage input. In this case, direct velocity output was chosen for the dynamic measurements because of the improved resolution and dropout insensitivity of the velocity output (Lawrence et al 2002). Thus, our measurement settings for the vibrometer are a measurement mode of FFT (fast Fourier transform) in complex averaging with a factor of 5, used FFT lines of 12,800, a velocity output of 1,000 mm/s V, an AC amplitude of 7.5 V for the internal generator, an external amplifier of 20·, an external resistor of 21.75 kX, an actual maximum voltage of *20.5 V, and a lens objective of 20·.…”

Section: Experimental-based Natural Frequency Of the Tunable Filtermentioning

confidence: 99%

Design, modeling, and mechanical characterizations of micromachined InP-based actuator for tunable MOEMS applications

et al. 2007

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A novel InP-based microactuator, which is actuated by electrostatic means, has been proposed, designed, fabricated, and characterized for tuning applications in the 1.5 lm wavelength domains. Its structural design is based on the global optimization method. The tunable device is a big square membrane, which is supported by four identical cantilever beams. The three alternating layers Si 3 N 4 /SiO 2 as a distributed Bragg reflector (DBR) mirror, which were previously reported, have been formed on the top of the membrane. Based on the optical interferometric measurements, the proposed Fabry-Perot filter has demonstrated a maximum deflection of *321 nm with an applied voltage up to 12 V, an average sensitivity of *27 nm/V, a pull-in voltage of 12.7 V, and a release voltage of 10.7 V. It is also observed that its natural frequency is 88.4 kHz. This measured frequency implies that the tuning speed of our device is fast for optical operations within 0.01 ms. In addition, our device's mirror remains so flat with a good planarity of 0.07°, which is strictly required for the filter's optical performance. This optical performance can be achieved, when the micromachined structure has a tuning displacement up to *38 nm with a low tuning voltage up to 5 V. When compared with the finite element models (FEM), which were generated by the commercialized software, Coventor TM , our experimental results agree well in terms of the natural frequency, pull-in voltage and deflections. Thus, our tunable filter, which is based on the optimized design, enables better performances including reduced actuation voltages, large pull-in voltage, improved device reliability, and fast switching times. Our device can also quickly snap back to the original position. In addition, the undesired spring-softening effect has been reduced.

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Section: Experimental-based Natural Frequency Of the Tunable Filtermentioning

confidence: 99%

Design, modeling, and mechanical characterizations of micromachined InP-based actuator for tunable MOEMS applications

et al. 2007

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“…Vibrations of the membrane were measured using a scanning laser Doppler vibrometer [11] integrated in a Polytec MSA-400. The measurement setup is shown schematically in figure 7.…”

Section: B Measurementsmentioning

confidence: 99%

Development of a biomimetic eardrum for acoustic sensing

2015

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The desert locust (schistocerca gregaria) has ears integrating sound reception, impedance transformation and frequency discrimination in a single passive membrane. The anatomy and frequency dependent response of these ears to acoustic input have been extensively studied before. This is the inspiration for the development of a new acoustic sensor with integrated mechanical filtering. We have worked on a new microfabrication process based on conformal deposition of Parylene on silicon which was used to make membranes with similar variations in tension, thickness and mass density as the tympanal membrane of the locust. Mapped vibration measurements show similarities in the behaviour of the artificial membrane with the biological original, showing the potential of the approach for future energy efficient passive mechanical filtering approaches.

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“…Then, the measured signal is scaled and shifted in phase to obtain the velocity signal. In our study, the true velocity of the mirror is directly measured using a Laser Doppler Vibrometer (LDV) unlike many of the earlier studies (Lawrence et al, 2002). The velocity signal is then amplified by an adjustable gain through an analog circuit and fed back to the system to change the effective damping of the mirror.…”

Section: Introductionmentioning

confidence: 99%

Adjusting the Vibratory Response of a Micro Mirror via Position and Velocity Feedback

Veryeri

Basdogan

2010

Journal of Vibration and Control

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We changed the vibratory (dynamic) response of a micro mirror experimentally using a feedback circuit. For this purpose, we first measured the vibrational velocity of the mirror using a Laser Doppler Vibrometer and then multiplied it with a gain and fed the signal back to the mirror to change its effective damping. We also investigate the influence of velocity and position feedback on the dynamic response of the same mirror through numerical simulations. For this purpose, first, a transfer function of the mirror was obtained based on the experimental frequency sweep data of the first two vibration modes. Then, the dynamic response of the mirror was investigated for different feedback gains via simulations. The results of our study show that the vibration amplitude or settling time of the mirror can be adjusted by altering the velocity feedback gain and the coupled vibration modes of the mirror can be separated from each other by adjusting the position feedback gain.

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<title>Laser Doppler vibrometry for optical MEMS</title>

Cited by 11 publications

References 0 publications

Design, modeling, and mechanical characterizations of micromachined InP-based actuator for tunable MOEMS applications

Design, modeling, and mechanical characterizations of micromachined InP-based actuator for tunable MOEMS applications

Development of a biomimetic eardrum for acoustic sensing

Adjusting the Vibratory Response of a Micro Mirror via Position and Velocity Feedback

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