Light-Pulse Atomic Interferometry for High Data Rate Navigation
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Solution Overview
Problem
Atom interferometer accelerometers have operated at data rates below a few Hertz, which is insufficient for navigation applications on dynamic platforms, necessitating a solution for increased data rates and miniaturization.
Innovation Solution
A light-pulse atomic interferometry device that launches two cold-atom clouds toward each other, allowing for rapid re-trapping and increased operation rates, achieving data rates of up to hundreds of Hertz with high sensitivity, and incorporating a magnetic field gradient profile and optical system to optimize atom exchange and detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional atom interferometer operation is used, then measurement sensitivity is maintained, but data rate remains below a few Hertz
Solution Approach 1:
The patent divides the atomic vapor into multiple distinct clouds, each capable of independent interferometric interrogation. This segmentation allows parallel processing of multiple atomic ensembles, thereby increasing the overall data rate without sacrificing measurement sensitivity in any single cloud.
Solution Approach 2:
The patent employs periodic modulation of the trapping potentials and laser pulses to rapidly cycle atoms through different interferometric sequences. This periodic action enables repeated measurements at high frequency, transforming the data rate from sub-Hertz to hundreds of Hertz while maintaining coherence through synchronized pulse timing.
2Productivity
If atom clouds are launched toward each other for rapid re-trapping, then operation rate increases to hundreds of Hertz, but device complexity increases
Solution Approach 1:
The patent designs the optical and magnetic field systems to serve multiple functions: trapping atomic clouds, launching clouds toward each other, performing Raman transitions for interferometry, and re-trapping atoms after interrogation. This multi-functionality reduces the need for separate dedicated systems for each operation, thereby managing complexity while enabling high operation rates.
Solution Approach 2:
The patent employs dynamically adjustable trapping potentials and magnetic field configurations that can be rapidly switched between different operational modes (trapping, launching, interrogating, re-trapping). This dynamic control allows the system to adapt its configuration in real-time, facilitating high-speed operation without requiring permanently complex hardware for each possible state.
3Volume of moving object
If miniaturization is pursued for dynamic platform applications, then device size is reduced, but atom interrogation time and sensitivity may be compromised
Solution Approach 1:
The patent uses multiple segmented atomic clouds within a compact volume, allowing parallel interferometric measurements to occur simultaneously. This segmentation enables the device to maintain high sensitivity through multiple independent measurement channels while fitting within a miniaturized form factor suitable for dynamic platforms.
Solution Approach 2:
The patent utilizes changes in atomic transition parameters and laser pulse sequences to achieve high-precision measurements within reduced physical dimensions. By optimizing the interferometric sequence parameters and atomic state manipulations, the system maintains measurement precision despite the reduced interrogation time and space available in a miniaturized device.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device enables navigation-grade data rates for measuring acceleration and rotation with high sensitivity and bias stability, facilitating miniaturization and improved performance in dynamic environments.
Implementation Method 1
The first pulse of a so-called 'π/2-π-π/2' sequence of optical pulses splits the atomic phase trajectories into the two interferometric 'arms' by exciting some atoms from a lower to a higher hyperfine level of the atomic ground state by means of a Raman transition in which photonic recoil induces a corresponding momentum state.
Implementation Method 2
two sets of magnetic coils configured to magnetically confine an atomic vapor in two respective magneto-optical traps (MOTs) within the vessel when activated
Implementation Method 3
an optical system configured to irradiate the atomic vapor within the vessel with laser radiation that, when suitably tuned, can launch atoms previously confined in each of the MOTs toward the other MOT
Implementation Method 4
a Raman transition in which photonic recoil induces a corresponding momentum state
Implementation Method 5
Phase differences between the two paths induced by acceleration or rotation are manifested as shifts in the relative populations of the different internal atomic states, as revealed by a state-selective detector such as a fluorescence or laser-absorption detector.
Implementation Method 6
The cooling beam along with the repump beam (respective frequencies νcool and νrepump, as indicated in the figure) are used to recapture, launch and cool the atoms
Data Source
AI summary
A light-pulse atomic interferometry (LPAI) apparatus is provided. The LPAI apparatus comprises a vessel, two sets of magnetic coils configured to magnetically confine an atomic vapor in two respective magneto-optical traps (MOTs) within the vessel when activated, and an optical system configured to irradiate the atomic vapor within the vessel with laser radiation that, when suitably tuned, can launch atoms previously confined in each of the MOTs toward the other MOT. In embodiments, the magnetic coils are configured to produce a magnetic field that is non-zero at the midpoint between the traps. In embodiments, the time-of-flight of the launched atoms from one MOT to the other is 12 ms or less. In embodiments, the MOTs are situated approximately 36 mm apart. In embodiments, the apparatus is configured to activate the magnetic coils according to a particular temporal magnetic field gradient profile.