5 research outputs found
Quantum Nondemolition Measurement of Discrete Fock States of a Nanomechanical Resonator
We study theoretically a radio frequency superconducting interference device
integrated with both a nanomechanical resonator and an LC one. By applying
adiabatic and rotating wave approximations, we obtain an effective Hamiltonian
that governs the dynamics of the mechanical and LC resonators. Nonlinear terms
in this Hamiltonian can be exploited for performing a quantum nondemolition
measurement of Fock states of the nanomechanical resonator. We address the
feasibility of experimental implementation and show that the nonlinear coupling
can be made sufficiently strong to allow the detection of discrete mechanical
Fock states
Displacement Detection with a Vibrating RF SQUID: Beating the Standard Linear Limit
We study a novel configuration for displacement detection consisting of a
nanomechanical resonator coupled to both, a radio frequency superconducting
interference device (RF SQUID) and to a superconducting stripline resonator. We
employ an adiabatic approximation and rotating wave approximation and calculate
the displacement sensitivity. We study the performance of such a displacement
detector when the stripline resonator is driven into a region of nonlinear
oscillations. In this region the system exhibits noise squeezing in the output
signal when homodyne detection is employed for readout. We show that
displacement sensitivity of the device in this region may exceed the upper
bound imposed upon the sensitivity when operating in the linear region. On the
other hand, we find that the high displacement sensitivity is accompanied by a
slowing down of the response of the system, resulting in a limited bandwidth
Displacement Detection with A Vibrating Rf Superconducting Interference Device: Beating the Standard Linear Limit
We study a configuration for displacement detection consisting of a nanomechanical resonator coupled to both a radio frequency superconducting interference device and to a superconducting stripline resonator. We employ an adiabatic approximation and rotating wave approximation and calculate the displacement sensitivity. We study the performance of such a displacement detector when the stripline resonator is driven into a region of nonlinear oscillations. In this region the system exhibits noise squeezing in the output signal when homodyne detection is employed for readout. We show that displacement sensitivity of the device in this region may exceed the upper bound imposed upon the sensitivity when operating in the linear region. On the other hand, we find that the high displacement sensitivity is accompanied by a slowing down of the response of the system, resulting in a limited bandwidth
Forced and self-excited oscillations of an optomechanical cavity
We experimentally study forced and self oscillations of an optomechanical
cavity which is formed between a fiber Bragg grating that serves as a static
mirror and between a freely suspended metallic mechanical resonator that serves
as a moving mirror. In the domain of small amplitude mechanical oscillations,
we find that the optomechanical coupling is manifested as changes in the
effective resonance frequency, damping rate and cubic nonlinearity of the
mechanical resonator. Moreover, self oscillations of the micromechanical mirror
are observed above a certain optical power threshold. A comparison between the
experimental results and a theoretical model that we have recently presented
yields a good agreement. The comparison also indicates that the dominant
optomechanical coupling mechanism is the heating of the metallic mirror due to
optical absorption.Comment: 11 pages, 6 figure