Ben Buchler

Non-Gaussian Mechanical Motion via Single and Multiphonon Subtraction from a Thermal State

Publisher: American Physical Society (APS)

Date: 08-12-2021

DOI: 10.1103/PHYSREVLETT.127.243601

Stationary Light in Atomic Media

Publisher: Wiley

Date: 30-04-2019

DOI: 10.1002/QUTE.201800100

Single-Phonon Addition and Subtraction to a Mechanical Thermal State

Publisher: American Physical Society (APS)

Date: 21-01-2021

DOI: 10.1103/PHYSREVLETT.126.033601

Fabrication of ultrahigh-precision hemispherical mirrors for quantum-optics applications

Publisher: Springer Science and Business Media LLC

Date: 09-01-2018

DOI: 10.1038/S41598-017-18637-8

Abstract: High precision, high numerical aperture mirrors are desirable for mediating strong atom-light coupling in quantum optics applications and can also serve as important reference surfaces for optical metrology. In this work we demonstrate the fabrication of highly-precise hemispheric mirrors with numerical aperture NA = 0.996. The mirrors were fabricated from aluminum by single-point diamond turning using a stable ultra-precision lathe calibrated with an in-situ white-light interferometer. Our mirrors have a diameter of 25 mm and were characterized using a combination of wide-angle single-shot and small-angle stitched multi-shot interferometry. The measurements show root-mean-square (RMS) form errors consistently below 25 nm. The smoothest of our mirrors has a RMS error of 14 nm and a peak-to-valley (PV) error of 88 nm, which corresponds to a form accuracy of λ /50 for visible optics.

Optical back-action on the photothermal relaxation rate

Publisher: Optica Publishing Group

Date: 02-02-2021

DOI: 10.1364/OPTICA.412182

Abstract: Photothermal effects can alter the response of an optical cavity, for ex le, by inducing self-locking behavior or unstable anomalies. The consequences of these effects are often regarded as parasitic and generally cause limited operational performance of the cavity. Despite their importance, however, photothermal parameters are usually hard to characterize precisely. In this work, we use an optical cavity strongly coupled to photothermal effects to experimentally observe an optical back-action on the photothermal relaxation rate. This effect, reminiscent of the radiation-pressure-induced optical spring effect in cavity optomechanical systems, uses optical detuning as a fine control to change the photothermal relaxation process. The photothermal relaxation rate of the system can be accordingly modified by more than an order of magnitude. This approach offers an opportunity to obtain precise in situ estimations of the parameters of the cavity in a way that is compatible with a wide range of optical resonator platforms. Through this back-action effect, we are able to determine the natural photothermal relaxation rate and the effective thermal conductivity of cavity mirrors with unprecedented resolution.

Photothermally induced transparency

Publisher: American Association for the Advancement of Science (AAAS)

Date: 21-02-2020

DOI: 10.1126/SCIADV.AAX8256

Abstract: Photothermal-cavity nonlinearity induces a new transparency effect with demonstrated agreement between model and experiment.

Brillouin optomechanics: From strong coupling to single-phonon-level operations

Publisher: SPIE

Date: 03-03-2022

DOI: 10.1117/12.2616725

Cancellation of photothermally induced instability in an optical resonator

Publisher: Optica Publishing Group

Date: 11-08-2022

DOI: 10.1364/OPTICA.457328

Abstract: Optical systems are often subject to parametric instability caused by the delayed response of the optical field to the system dynamics. In some cases, parasitic photothermal effects aggravate the instability by adding new interaction dynamics. This may lead to the possible insurgence or lification of parametric gain that can further destabilize the system. In this paper, we show that the photothermal properties of an optomechanical cavity can be modified to mitigate or even completely cancel optomechanical instability. By inverting the sign of the photothermal interaction to let it cooperate with radiation pressure, we achieve control of the system dynamics to be fully balanced around a stable equilibrium point. Our study provides a feedback solution for optical control and precise metrological applications, specifically in high-sensitivity resonating systems that are particularly susceptible to parasitic photothermal effects, such as our test case of a macroscopic optical levitation setup. This passive stabilization technique is beneficial for improving system performance limited by photothermal dynamics in broad areas of optics, optomechanics, photonics, and laser technologies.

Observation of cross phase modulation in cold atom gradient echo memory

Publisher: IOP Publishing

Date: 09-2022

DOI: 10.1088/1367-2630/AC8C64

Abstract: Strong nonlinear interactions between single photons have important applications in optical quantum information processing. Demonstrations of these interactions in cold atomic ensembles have largely been limited to exploiting slow light generated using electromagnetically induced transparency (EIT). However, these EIT implementations have limited achievable phase shifts due to spontaneous emission. Here, we demonstrate and characterize a scheme free from these limitations using gradient echo memory with inferred single photon phase shifts of 0.07 ± 0.02 μ rad. Excellent agreement with theoretical modelling was observed. Degradation of memory efficiency was observed for large phase shifts but strategies to overcome that are presented.

Observation of nonlinear dynamics in an optical levitation system

Publisher: Springer Science and Business Media LLC

Date: 04-11-2020

DOI: 10.1038/S42005-020-00467-2

Abstract: Optical levitation of mechanical oscillators has been suggested as a promising way to decouple the environmental noise and increase the mechanical quality factor. Here, we investigate the dynamics of a free-standing mirror acting as the top reflector of a vertical optical cavity, designed as a testbed for a tripod cavity optical levitation setup. To reach the regime of levitation for a milligram-scale mirror, the optical intensity of the intracavity optical field approaches 3 MW cm −2 . We identify three distinct optomechanical effects: excitation of acoustic vibrations, expansion due to photothermal absorption, and partial lift-off of the mirror due to radiation pressure force. These effects are intercoupled via the intracavity optical field and induce complex system dynamics inclusive of high-order sideband generation, optical bistability, parametric lification, and the optical spring effect. We modify the response of the mirror with active feedback control to improve the overall stability of the system.

Radiation tolerance of two-dimensional material-based devices for space applications

Publisher: Springer Science and Business Media LLC

Date: 13-03-2019

DOI: 10.1038/S41467-019-09219-5

Abstract: Characteristic for devices based on two-dimensional materials are their low size, weight and power requirements. This makes them advantageous for use in space instrumentation, including photovoltaics, batteries, electronics, sensors and light sources for long-distance quantum communication. Here we present a comprehensive study on combined radiation effects in Earth’s atmosphere on various devices based on these nanomaterials. Using theoretical modeling packages, we estimate relevant radiation levels and then expose field-effect transistors, single-photon sources and monolayers as building blocks for future electronics to γ -rays, protons and electrons. The devices show negligible change in performance after the irradiation, suggesting robust suitability for space use. Under excessive γ -radiation, however, monolayer WS 2 shows decreased defect densities, identified by an increase in photoluminescence, carrier lifetime and a change in doping ratio proportional to the photon flux. The underlying mechanism is traced back to radiation-induced defect healing, wherein dissociated oxygen passivates sulfur vacancies.

Search for topological defect dark matter using the global network of optical magnetometers for exotic physics searches (GNOME)

Publisher: Research Square Platform LLC

Date: 07-04-2021

DOI: 10.21203/RS.3.RS-298059/V1

Abstract: Results are reported from the first full-scale search for transient signals from exotic fields of astrophysical origin using data from a newly constructed Earth-scale detector: the Global Network of Optical Magnetometers for Exotic physics searches (GNOME). Data collected by the GNOME consist of correlated measurements from optical atomic magnetometers located in laboratories all over the world. GNOME data are searched for patterns of signals propagating through the network consistent with exotic fields composed of ultralight bosons such as axion-like particles (ALPs). Analysis of data from a continuous month-long operation of the GNOME finds no statistically significant signals consistent with those expected due to encounters with topological defects (axion domain walls), placing new experimental constraints on such dark matter scenarios.

Search for topological defect dark matter with a global network of optical magnetometers

Publisher: Springer Science and Business Media LLC

Date: 12-2021

DOI: 10.1038/S41567-021-01393-Y

Abstract: Ultralight bosons such as axion-like particles are viable candidates for dark matter. They can form stable, macroscopic field configurations in the form of topological defects that could concentrate the dark matter density into many distinct, compact spatial regions that are small compared with the Galaxy but much larger than the Earth. Here we report the results of the search for transient signals from the domain walls of axion-like particles by using the global network of optical magnetometers for exotic (GNOME) physics searches. We search the data, consisting of correlated measurements from optical atomic magnetometers located in laboratories all over the world, for patterns of signals propagating through the network consistent with domain walls. The analysis of these data from a continuous month-long operation of GNOME finds no statistically significant signals, thus placing experimental constraints on such dark matter scenarios.

Australian National University

Location: Australia

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ETH Zürich

Location: Switzerland

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Discovery Projects - Grant ID: DP180103238

Start Date: 2018

End Date: 12-2022

Amount: $402,934.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP150101188

Start Date: 04-2016

End Date: 12-2020

Amount: $350,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP150101035

Start Date: 2015

End Date: 10-2015

Amount: $473,400.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE100100009

Start Date: 2010

End Date: 12-2011

Amount: $455,000.00

Funder: Australian Research Council

ARC Future Fellowships - Grant ID: FT100100048

Start Date: 03-2011

End Date: 03-2015

Amount: $577,882.00

Funder: Australian Research Council

ARC Centres Of Excellence - Grant ID: CE1101027

Start Date: 07-2011

End Date: 12-2017

Amount: $24,500,000.00

Funder: Australian Research Council

ARC Centres Of Excellence - Grant ID: CE170100012

Start Date: 06-2018

End Date: 05-2025

Amount: $33,700,000.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE200100032

Start Date: 2020

End Date: 12-2022

Amount: $600,000.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE0882531

Start Date: 2008

End Date: 12-2009

Amount: $250,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP1092891

Start Date: 2010

End Date: 12-2012

Amount: $300,000.00

Funder: Australian Research Council