7 research outputs found
Detecting and characterizing frequency fluctuations of vibrational modes
We show how frequency fluctuations of a vibrational mode can be separated
from other sources of phase noise. The method is based on the analysis of the
time dependence of the complex amplitude of forced vibrations. The moments of
the complex amplitude sensitively depend on the frequency noise statistics and
its power spectrum. The analysis applies to classical and to quantum
vibrations
Frequency fluctuations in silicon nanoresonators
Frequency stability is key to performance of nanoresonators. This stability
is thought to reach a limit with the resonator's ability to resolve
thermally-induced vibrations. Although measurements and predictions of
resonator stability usually disregard fluctuations in the mechanical frequency
response, these fluctuations have recently attracted considerable theoretical
interest. However, their existence is very difficult to demonstrate
experimentally. Here, through a literature review, we show that all studies of
frequency stability report values several orders of magnitude larger than the
limit imposed by thermomechanical noise. We studied a monocrystalline silicon
nanoresonator at room temperature, and found a similar discrepancy. We propose
a new method to show this was due to the presence of frequency fluctuations, of
unexpected level. The fluctuations were not due to the instrumentation system,
or to any other of the known sources investigated. These results challenge our
current understanding of frequency fluctuations and call for a change in
practices