Publications by Amir Hossein Ghadimi

Generalized dissipation dilution in strained mechanical resonators

Tobias Kippenberg, Amir Hossein Ghadimi, Ryan Daniel Schilling, Dalziel Joseph Wilson, Sergey Fedorov, Nils Johan Engelsen

Mechanical resonators with high quality factors are widely used in precision experiments, ranging from gravitational wave detection and force sensing to quantum optomechanics. Beams and membranes are well known to exhibit flexural modes with enhanced quali ...

AMER PHYSICAL SOC2019

Ultralow Dissipation Mechanical Resonators for Quantum Optomechanics

Tobias Kippenberg, Amir Hossein Ghadimi, Ryan Daniel Schilling, Dalziel Joseph Wilson, Sergey Fedorov, Nils Johan Engelsen, Alberto Beccari

We demonstrate dissipation dilution engineering techniques for ultralow dissipation mechanical resonators. The Si3N4 nanobeams show quality factors (Q) as high as 800 million and Q x f exceeding 10(15) Hz-both records at room temperature. (C) 2019 The Auth ...

IEEE2019

Clamp-Tapering Increases the Quality Factor of Stressed Nanobeams

Tobias Kippenberg, Amir Hossein Ghadimi, Ryan Daniel Schilling, Dalziel Joseph Wilson, Sergey Fedorov, Nils Johan Engelsen, Alberto Beccari

Stressed nanomechanical resonators are known to have exceptionally high quality factors (Q) due to the dilution of intrinsic dissipation by stress. Typically, the amount of dissipation dilution and thus the resonator Q is limited by the high mode curvature ...

AMER CHEMICAL SOC2019

Elastic strain engineering for ultralow mechanical dissipation

Tobias Kippenberg, Amir Hossein Ghadimi, Ryan Daniel Schilling, Dalziel Joseph Wilson, Sergey Fedorov, Nils Johan Engelsen

Extreme stresses can be produced in nanoscale structures, a feature which has been used to realize enhanced materials properties, such as the high mobility of silicon in modern transistors. Here we show how nanoscale stress can be used to realize exception ...

American Association for the Advancement of Science2018

Ultra-coherent nano-mechanical resonators for quantum optomechanics at room temperature

Amir Hossein Ghadimi

Mechanical oscillators are among the most important scientific tools in the modern physics. From the pioneering experiments in 18th by founding fathers of modern physics such as Newton, Hooke and Cavendish to the ground braking experiments in the 21th cent ...

EPFL2018

Elastic strain engineering for ultralow mechanical dissipation

Tobias Kippenberg, Amir Hossein Ghadimi, Ryan Daniel Schilling, Dalziel Joseph Wilson, Sergey Fedorov, Nils Johan Engelsen

Extreme stresses can be produced in nanoscale structures, a feature which has been used to realize enhanced materials properties, such as the high mobility of silicon in modern transistors. Here we show how nanoscale stress can be used to realize exception ...

IEEE2018

Appearance and Disappearance of Quantum Correlations in Measurement-Based Feedback Control of a Mechanical Oscillator

Tobias Kippenberg, Vivishek Sudhir, Amir Hossein Ghadimi, Ryan Daniel Schilling, Dalziel Joseph Wilson, Hendrik Schütz, Sergey Fedorov

Quantum correlations between imprecision and backaction are a hallmark of continuous linear measurements. Here, we study how measurement-based feedback can be used to improve the visibility of quantum correlations due to the interaction of a laser field wi ...

American Physical Society2017

Radiation and Internal Loss Engineering of High-Stress Silicon Nitride Nanobeams

Amir Hossein Ghadimi, Dalziel Joseph Wilson

High-stress Si3N4 nanoresonators have become an attractive choice for electro- and optomechanical devices. Membrane resonators can achieve quality factor (Q)frequency (f) products exceeding 10(13) Hz, enabling (in principle) quantum coherent operation at r ...

Amer Chemical Soc2017

Near-Field Integration of a Si3N4 Nanobeam and a SiO2 Microcavity for Heisenberg-Limited Displacement Sensing

Tobias Kippenberg, Vivishek Sudhir, Amir Hossein Ghadimi, Ryan Daniel Schilling, Dalziel Joseph Wilson

A single-chip radio-frequency optomechanical system, consisting of a Si3N4 nanobeam in the evanescent near-field of a SiO2 optical microdisk resonator realizes displacement imprecision >30dB below the standard quantum limit at room-temperature. ...

Ieee2016

Near-Field Integration of a SiN Nanobeam and a SiO2 Microcavity for Heisenberg-Limited Displacement Sensing

Tobias Kippenberg, Vivishek Sudhir, Amir Hossein Ghadimi, Ryan Daniel Schilling, Dalziel Joseph Wilson

Placing a nanomechanical object in the evanescent near field of a high-Q optical microcavity gives access to strong gradient forces and quantum-limited displacement readout, offering an attractive platform for both precision sensing technology and basic qu ...

American Physical Society (APS)2016

Measurement-based control of a mechanical oscillator at its thermal decoherence rate

Tobias Kippenberg, Vivishek Sudhir, Nicolas Piro Mastracchio, Amir Hossein Ghadimi, Ryan Daniel Schilling, Dalziel Joseph Wilson

In real-time quantum feedback protocols(1,2), the record of a continuous measurement is used to stabilize a desired quantum state. Recent years have seen successful applications of these protocols in a variety of well-isolated micro-systems, including micr ...

Nature Publishing Group2015