Publications by Nils Johan Engelsen

Motional Sideband Asymmetry of a Solid-State Mechanical Resonator at Room Temperature

Tobias Kippenberg, Alberto Beccari, Amirali Arabmoheghi, Nils Johan Engelsen, Guanhao Huang

The motional sideband asymmetry of a mechanical oscillator interacting with a laser field can be observed when approaching the quantum ground state, where the zero-point energy of the mechanical oscillator becomes a sizable contribution to its motion. In t ...

2025

Ultrahigh-quality-factor micro- and nanomechanical resonators using dissipation dilution

Tobias Kippenberg, Alberto Beccari, Nils Johan Engelsen

Mechanical resonators are widely used in sensors, transducers and optomechanical systems, where mechanical dissipation sets the ultimate limit to performance. Over the past 15 years, the quality factors in strained mechanical resonators have increased by f ...

Nature Portfolio2024

Room-temperature quantum optomechanics using an ultralow noise cavity

Tobias Kippenberg, Alberto Beccari, Nils Johan Engelsen, Guanhao Huang

At room temperature, mechanical motion driven by the quantum backaction of light has been observed only in pioneering experiments in which an optical restoring force controls the oscillator stiffness1,2. For solid-state mechanical resonators in which oscil ...

Nature Portfolio2024

Framework of Free-Electron Quantum Optics Using Photonic Integrated Circuits

Tobias Kippenberg, Nils Johan Engelsen, Guanhao Huang

We develop a framework of using photonic integrated circuits for free-electron quantum optics applications. We formulate the interaction using a three-dimensional QED quantization procedure, and discuss a few fundamental limitations and specific applicatio ...

Optical Society of America2023

Ultralow Dissipation Mechanical Resonators for Cavity-Free Quantum Control

Tobias Kippenberg, Alberto Beccari, Amirali Arabmoheghi, Nils Johan Engelsen, Guanhao Huang

We fabricate nanomechanical resonators with Q > 109 at room temperature and show efficient optical readout of their motion. With an improved interferometer, these devices can be cooled close to the ground state without a cavity. ...

Optical Society of America2023

Perimeter Modes of Nanomechanical Resonators Exhibit Quality Factors Exceeding 10(9) at Room Temperature

Tobias Kippenberg, Alberto Beccari, Amirali Arabmoheghi, Nils Johan Engelsen, Guanhao Huang, Sergey Fedorov

Systems with low mechanical dissipation are extensively used in precision measurements such as gravitational wave detection, atomic force microscopy, and quantum control of mechanical oscillators via optomechanics and electromechanics. The mechanical quali ...

American Physical Society2022

Strained crystalline nanomechanical resonators with quality factors above 10 billion

Tobias Kippenberg, Sergey Fedorov, Alberto Beccari, Nils Johan Engelsen

In strained mechanical resonators, the concurrence of tensile stress and geometric nonlinearity dramatically reduces dissipation. This phenomenon, called dissipation dilution, is employed in mirror suspensions of gravitational-wave interferometers and at t ...

NATURE PORTFOLIO2022

Hierarchical tensile structures with ultralow mechanical dissipation

Tobias Kippenberg, Sergey Fedorov, Alberto Beccari, Amirali Arabmoheghi, Nils Johan Engelsen

Structural hierarchy is found in myriad biological systems and has improved man-made structures ranging from the Eiffel tower to optical cavities. In mechanical resonators whose rigidity is provided by static tension, structural hierarchy can reduce the di ...

Nature Portfolio2022

High-yield, wafer-scale fabrication of ultralow-loss, dispersion-engineered silicon nitride photonic circuits

Tobias Kippenberg, Rui Ning Wang, Junqiu Liu, Arslan Sajid Raja, Jijun He, Guanhao Huang, Nils Johan Engelsen, Tianyi Liu

Low-loss photonic integrated circuits and microresonators have enabled a wide range of applications, such as narrow-linewidth lasers and chip-scale frequency combs. To translate these into a widespread technology, attaining ultralow optical losses with est ...

Nature Research2021

A high-cooperativity, nano-optomechanical system comprised of high stress Si3N4

Tobias Kippenberg, Amirali Arabmoheghi, Nils Johan Engelsen

We report the design fabrication and characterization of a monolithic nano-optomechanical transducer comprised of high stress silicon nitride (Si3N4). Our system features a one dimensional Fabry-Perot photonic crystal cavity (Q approximate to 10(5)) integr ...

IEEE2021