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(Color online) Schematic of the experiment, with SEM images of the resonators. The optical measurement is depicted in (a); note that the paddle-shaped resonator is electrostatically driven. A rf lock-in amplifier reads the photodetector signal. All optical measurements are carried out at room temperature. For doubly clamped resonators, a schematic of the magnetomotive technique is shown in (b).
(Color online) The amplitude (a) and phase (b) of a GaAs paddle-shaped resonator as a function of driving frequency. The solid line in (a) traces a Lorentzian fit. The resonant frequency is , with a quality factor of 410. Changes in the resonant frequency as a function of applied bias are plotted in (c) and (d). Changes in the factor are plotted in the inset of (d).
(Color online) A GaAs doubly clamped beam resonator is characterized by the magnetomotive technique. The resonant frequency is , with a factor of 11 000 (a). A Lorentzian fit to the data is shown as a solid line. The inset shows the corresponding phase information. The responses of the system to different driving amplitudes at a fixed temperature and magnetic field are plotted in (b). The induced EMF increases linearly with driving amplitude up to . The points A, B, C, D, and E represent , , , , and , respectively. The effect of magnetic field intensity on the resonance is depicted in (c); the inset depicts the expected quadratic behavior. Finally, (d) demonstrates the quadratic dependence of dissipation on the applied magnetic field. The error bars are derived by fitting a Lorentzian function to the resonances.
(Color online) For these data, a GaAs doubly clamped beam resonator similar to that characterized in Fig. 3 is placed in a dilution refrigerator with an superconducting magnet and a base temperature of . The resonator is actuated with in a field. The temperature dependence of the energy dissipation is shown in (a). The energy dissipation increases according to the power law . Degradation of the mechanical resonance is evident in (b), which shows the frequency shift as a function of temperature. The dashed lines are drawn as a guide to the eye. The factor decreases from 17 000 to 3500 as the temperature increases from . The temperature dependence of the resonant frequency is shown in (c); logarithmic behavior appears below .
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