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We have fabricated large (≤400 μm diameter) high tensile stress SiN membrane mechanical resonators and measured the resonant frequency and quality factors (Q) of different modes of oscillation using optical interferometric detection. We observe that the dissipation (Q-1) is limited by clamping loss for pure radial modes, but higher order azimuthal modes are limited by a mechanism which appears to be intrinsic to the material. The observed dissipation is strongly dependent on size of the membrane and mode type. Appropriate choice of size and operating mode allows the selection of optimum resonator designs for applications in mass sensing and optomechanical experiments. [ABSTRACT FROM AUTHOR]

We examine the relationship between squeeze film effects and resonance frequency in drum-type resonators. We find that the resonance frequency increases linearly with pressure as a result of the additional restoring force contribution from compression of gas within the drum cavity. We demonstrate trapping of the gas by squeeze film effects and geometry. The pressure sensitivity is shown to scale inversely with cavity height and sound radiation is found to be the predominant loss mechanism near and above atmospheric pressure. Drum resonators exhibit linearity and sensitivity suitable to barometry from below 10 Torr up to several atmospheres. [ABSTRACT FROM AUTHOR]

We report on the optical parametric excitation of silicon nanomechanical resonant structures. The threshold laser power needed to set these structures into self-oscillation was estimated to be around 70 μW. We measured resonant frequencies of up to 38 MHz by optical excitation; this method should extend to much higher frequencies. Under optical amplification of motion, the spectral response at resonance narrowed to the equivalent of a mechanical quality factor >20 000 at room temperature. These structures act as frequency tunable passive modulators of light, requiring no additional drive. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]