scholarly journals Probing gravity by holding atoms for 20 seconds

Science ◽  
2019 ◽  
Vol 366 (6466) ◽  
pp. 745-749 ◽  
Author(s):  
Victoria Xu ◽  
Matt Jaffe ◽  
Cristian D. Panda ◽  
Sofus L. Kristensen ◽  
Logan W. Clark ◽  
...  
Keyword(s):  
Noise Source ◽  
Optical Cavity ◽  
Hold Time ◽  
Gravitational Potential Energy ◽  
Vertical Separation ◽  
Fundamental Physics ◽  
Sensing Applications ◽  
Interferometer Phase ◽  
Phase Variance ◽  
Atom Interferometers

Atom interferometers are powerful tools for both measurements in fundamental physics and inertial sensing applications. Their performance, however, has been limited by the available interrogation time of freely falling atoms in a gravitational field. By suspending the spatially separated atomic wave packets in a lattice formed by the mode of an optical cavity, we realize an interrogation time of 20 seconds. Our approach allows gravitational potentials to be measured by holding, rather than dropping, atoms. After seconds of hold time, gravitational potential energy differences from as little as micrometers of vertical separation generate megaradians of interferometer phase. This trapped geometry suppresses the phase variance due to vibrations by three to four orders of magnitude, overcoming the dominant noise source in atom-interferometric gravimeters.

Cold atom interferometry for inertial sensing in the field

2020 ◽  
Vol 9 (5) ◽  
pp. 221-225
Author(s):  
Ravi Kumar ◽  
Ana Rakonjac
Keyword(s):  
High Precision ◽  
Cold Atoms ◽  
Cold Atom ◽  
Atom Interferometry ◽  
Precision Measurements ◽  
Inertial Sensing ◽  
Fundamental Physics ◽  
Recent Developments ◽  
Resource Exploration ◽  
Atom Interferometers

AbstractAtom interferometry is one of the most promising technologies for high precision measurements. It has the potential to revolutionise many different sectors, such as navigation and positioning, resource exploration, geophysical studies, and fundamental physics. After decades of research in the field of cold atoms, the technology has reached a stage where commercialisation of cold atom interferometers has become possible. This article describes recent developments, challenges, and prospects for quantum sensors for inertial sensing based on cold atom interferometry techniques.

scholarly journals Atom interferometers and optical atomic clocks: New quantum sensors for fundamental physics experiments in space

2007 ◽  
Vol 166 ◽  
pp. 159-165 ◽  
Author(s):  
G.M. Tino ◽  
L. Cacciapuoti ◽  
K. Bongs ◽  
Ch.J. Bordé ◽  
P. Bouyer ◽  
...  
Keyword(s):  
Atomic Clocks ◽  
Fundamental Physics ◽  
Physics Experiments ◽  
Atom Interferometers

scholarly journals Bound in the continuum modes in indirectly-patterned hyperbolic media

2021 ◽  
Author(s):  
Frank Koppens ◽  
Hanan Herzig-Sheinfux ◽  
Lorenzo Orsini ◽  
Minwoo Jung ◽  
Iacopo Torre ◽  
...  
Keyword(s):  
Near Field ◽  
Optical Cavity ◽  
Bound State ◽  
Destructive Interference ◽  
Dramatic Improvement ◽  
Quality Factors ◽  
Strong Light ◽  
Sensing Applications ◽  
The Continuum ◽  
Nanoscale Level

Abstract A conventional optical cavity supports one or more modes, which are confined since they are unable to leak out of the cavity. Bound state in continuum (BIC) cavities are an unconventional alternative, based on confinement by destructive interference, even though optical leakage channels are available. BICs are a general wave phenomenon, of particular interest to optics, but BICs have never been demonstrated at the nanoscale level. Nanoscale BIC cavities are more challenging to realize, however, as they require destructive interference at the nanometer scale. Here, we demonstrate the first nanophotonic cavities based on BIC and find an unprecedented combination of quality factors and ultrasmall mode volume. In particular, we exploit hyperbolic media, HyM, as they can support large (in principle unlimited) momentum excitations, which propagate as ultra-confined rays, so that HyM cavities can in principle be extremely small. However, building a hyperbolic BIC (hBIC) cavity presents a fundamental challenge: an hBIC has an infinite number of modes, which would all need to interfere simultaneously. Here, we bring the BIC concept to the nanoscale by introducing and demonstrating a novel multimodal reflection mechanism of the ray-like optical excitations in hyperbolic materials. Using near-field microscopy, we demonstrate mid-IR confinement in BIC-based nanocavities with volumes down to 23x23x3〖nm〗^3 and quality factors above 100 – a dramatic improvement in several metrics of confinement. This alliance of HyM with BICs yields a radically novel way to confine light and is expected to have far reaching consequences wherever strong optical confinement is utilized, from ultra-strong light-matter interactions, to mid-IR nonlinear optics and a range of sensing applications.

scholarly journals Circulating pulse cavity enhancement as a method for extreme momentum transfer atom interferometry

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Rustin Nourshargh ◽  
Samuel Lellouch ◽  
Sam Hedges ◽  
Mehdi Langlois ◽  
Kai Bongs ◽  
...  
Keyword(s):  
Laser Power ◽  
Large Scale ◽  
Optical Cavity ◽  
Optical Power ◽  
Atom Interferometry ◽  
Strain Sensitivity ◽  
Intracavity Frequency ◽  
Spatially Resolved ◽  
Light Scalar ◽  
Atom Interferometers

AbstractLarge-scale atom interferometers promise unrivaled strain sensitivity to mid-band gravitational waves, and will probe a new parameter space in the search for ultra-light scalar dark matter. These proposals require gradiometry with kilometer-scale baselines, a momentum separation above 104ℏk between interferometer arms, and optical transitions to long-lived clock states to reach the target sensitivities. Prohibitively high optical power and wavefront flatness requirements have thus far limited the maximum achievable momentum splitting. Here we propose a scheme for optical cavity enhanced atom interferometry, using circulating, spatially resolved pulses, and intracavity frequency modulation to meet these requirements. We present parameters for the realization of 20 kW circulating pulses in a 1 km interferometer enabling 104ℏk splitting on the 698 nm clock transition in 87Sr. This scheme addresses the presently insurmountable laser power requirements and is feasible in the context of a kilometer-scale atom interferometer facility.

scholarly journals A System-Level Modelling of Noise in Coupled Resonating MEMS Sensors

2020 ◽  
Vol 3 (1) ◽  
pp. 5
Author(s):  
Vinayak Pachkawade
Keyword(s):  
Noise Source ◽  
Operating Conditions ◽  
Sensor System ◽  
System Level ◽  
Mems Sensors ◽  
Noise Sources ◽  
System A ◽  
Sensing Applications ◽  
Mechanical Noise ◽  
The Impact

This paper presents realistic system-level modeling of effective noise sources in a coupled resonating mode-localized MEMS sensors. A governing set of differential equations are used to build a numerical model of a mechanical noise source in a coupled-resonator sensor and an effective thermo-mechanical noise is quantified through the simulation performed via SIMULINK. On a similar note, an effective noise that stems from the electronic readout used for the coupled resonating MEMS sensors is also quantified. Various noise sources in electronic readout are identified and the contribution of each is quantified. A comparison between an effective mechanical and electronic noise in a sensor system aids in identifying the dominant noise source in a sensor system. A method to optimize the system noise floor for an amplitude-based readout is presented. The proposed models present a variety of operating conditions, such as finite quality factor, varying coupled electrostatic spring strength, and operation with in-phase and out-of-phase mode. The proposed models aim to study the impact of fundamental noise processes that govern the ultimate resolution into a coupled resonating system used for various sensing applications.

Macroscopic scale atom interferometers: introduction, techniques, and applications

2019 ◽  
pp. 221-291
Author(s):  
Tim Kovachy ◽  
Alex Sugarbaker ◽  
Remy Notermans ◽  
Peter Asenbaum ◽  
Chris Overstreet ◽  
...  
Keyword(s):  
Atom Interferometry ◽  
Velocity Spread ◽  
Atom Optics ◽  
Large Momentum ◽  
Low Velocity ◽  
Macroscopic Scale ◽  
Wide Range ◽  
Atomic Fountain ◽  
Interferometer Phase ◽  
Atom Interferometers

This chapter introduces the fundamental principles and some of the applications of light-pulse atom interferometry. It includes tutorials on various atom optics techniques and on interferometer phase shift calculations. Recent advances in large momentum transfer atom optics and in the generation and manipulation of ultra-low-velocity-spread atom clouds have enabled atom interferometers that cover macroscopic scales in space (tens of centimeters) and in time (multiple seconds), dramatically improving interferometer sensitivity in a wide range of applications. This chapter reviews these advances and recent experiments performed with macroscopic scale atom interferometers in the 10-meter-tall atomic fountain at Stanford.

scholarly journals Optical Polarimetry for Fundamental Physics

Universe ◽  
2021 ◽  
Vol 7 (7) ◽  
pp. 252
Author(s):  
Guido Zavattini ◽  
Federico Della Valle
Keyword(s):  
Signal To Noise Ratio ◽  
Optical Cavity ◽  
Heterodyne Detection ◽  
Optical Scheme ◽  
Dipole Magnet ◽  
Fundamental Physics ◽  
Noise Floor ◽  
Electron Positron ◽  
Strong Candidate ◽  
Virtual Pairs

Sensitive magneto-optical polarimetry was proposed by E. Iacopini and E. Zavattini in 1979 to detect vacuum electrodynamic non-linearity, in particular Vacuum Magnetic Birefringence (VMB). This process is predicted in QED via the fluctuation of electron–positron virtual pairs but can also be due to hypothetical Axion-Like Particles (ALPs) and/or MilliCharged Particles (MCP). Today ALPs are considered a strong candidate for Dark Matter. Starting in 1992 the PVLAS collaboration, financed by INFN, Italy, attempted to measure VMB conceptually following the original 1979 scheme based on an optical cavity permeated by a time-dependent magnetic field and heterodyne detection. Two setups followed differing basically in the magnet: the first using a rotating superconducting 5.5 T dipole magnet at the Laboratori Nazionali di Legnaro, Legnaro, Italy and the second using two rotating permanent 2.5 T dipole magnets at the INFN section of Ferrara. At present PVLAS is the experiment which has set the best limit in VMB reaching a noise floor within a factor 7 of the predicted QED signal: Δn(QED)=2.5×10−23 @ 2.5 T. It was also shown that the noise floor was due to the optical cavity and a larger magnet is the only solution to increase the signal to noise ratio. The PVLAS experiment ended at the end of 2018. A new effort, VMB@CERN, which plans to use a spare LHC dipole magnet at CERN with a new modified optical scheme, is now being proposed. In this review, a detailed description of the PVLAS effort and the comprehension of its limits leading to a new proposal will be given.

A Prototype for a Palm-sized Photoacoustic Sensing Unit

2015 ◽  
Vol 1 (1) ◽  
Author(s):  
Fei Gao ◽  
Xiaohua Feng ◽  
Xilin Miao ◽  
Yuanjin Zheng
Keyword(s):  
Imaging Techniques ◽  
Low Cost ◽  
Low Frequency ◽  
Pulse Signal ◽  
Research Progress ◽  
Fundamental Physics ◽  
Sensing Applications ◽  
Data Acquisition Card ◽  
Potential Applications ◽  
The Cost

AbstractPhotoacoustic sensing and imaging techniques have experienced tremendous research progress, ranging from fundamental physics and methodologies to various biomedical and clinical applications in recent years. However, the state-of-art photoacoustic systems still suffer from high cost and bulky size, which hinders their potential applications for low-cost and portable diagnostics. In this paper, we propose the design for a palm-size photoacoustic sensor prototype. The design’s lower cost and smaller size would allow it to be used for portable photoacoustic sensing applications like oxygen saturation and temperature. By converting the high-frequency photoacoustic pulse signal to low-frequency photoacoustic DC signal through a rectifier circuit, the proposed photoacoustic receiver could potentially reduce the cost and device size efficiently, compared with the conventional highspeed data acquisition card interfaced with computer solutions. Preliminary testing is demonstrated to show its feasibility for photoacoustic sensing applications.

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