Multi-Beam Laser Intensity Stabilization With Continuous Integrating Filter
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Solution Overview
Problem
Current methods for stabilizing laser beam intensity in trapped ion quantum computers are slow and cannot correct for fluctuations on timescales faster than 10 minutes, failing to account for changes due to laser beam pointing, ion position, or air pressure fluctuations.
Innovation Solution
A method and system for fast intensity stabilization of laser beams in trapped ion systems, involving parallel measurements of laser beam intensity fluctuations at each ion and adjustment using a multi-channel acousto-optic modulator, with an integrating filter to reduce shot noise, allowing for frequent calibration and stabilization of multiple laser beams concurrently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If periodic calibration scanning is used to measure laser beam intensity, then measurement accuracy at ion position is improved, but stabilization speed deteriorates (taking 30 seconds to a minute per calibration)
Solution Approach 1:
The patent applies preliminary action by performing rapid intensity measurements at multiple predetermined positions along the laser beam path before the ion arrives or while the ion is trapped. These preliminary measurements establish intensity values at known positions, which are then used to interpolate the intensity at the ion's actual position, eliminating the need for slow scanning calibration when the ion is present.
Solution Approach 2:
The patent uses copying by measuring laser beam intensity at multiple predetermined positions along the beam path and creating a set of reference intensity values. These copied measurements at different positions are then used to determine the intensity at the ion's position through interpolation, providing accurate intensity data without requiring time-consuming scanning at the final position.
2Stability of the object's composition
If laser beam intensity is stabilized using photodiode feedback, then power stability is improved, but correction of pointing and position fluctuations is lost
Solution Approach 1:
The patent uses the ion itself as an intermediary to measure laser beam intensity. By detecting the ion's response (such as fluorescence or state changes) to the laser beam, the system obtains direct intensity measurements at the ion's position, which accounts for all fluctuations including pointing and position changes. This intermediary measurement approach provides more reliable intensity data than remote photodiode monitoring.
3Productivity
If fast stabilization is implemented, then fluctuation correction speed is improved, but measurement noise increases
Solution Approach 1:
The patent performs multiple intensity measurements at predetermined positions along the laser beam path before making stabilization adjustments. By collecting multiple preliminary measurements and using interpolation to determine the intensity at the ion's position, the system achieves fast stabilization while averaging out random noise through multiple samples.
Solution Approach 2:
The patent replaces slow mechanical scanning calibration with a faster computational approach. Instead of physically scanning the laser beam to measure intensity at the ion position, the system uses predetermined position measurements and mathematical interpolation to rapidly calculate the intensity, substituting mechanical movement with computational processing that is both faster and less noisy.
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
Enables rapid stabilization of laser beam intensity, compensating for fast fluctuations and maintaining constant intensity over time, improving system performance by allowing measurements and adjustments every few milliseconds, significantly faster than existing methods.
Implementation Method 1
adjust an amplitude of a radio frequency (RF) signal applied to an acousto-optic modulator (AOM) that controls the laser beam
Implementation Method 2
monitor the power of the laser beam with a photodiode
Data Source
AI summary
Aspects of the present disclosure describe techniques for fast stabilization of multiple controller beams with continuous integrating filter. For example, a method is described for intensity stabilization of laser beams (e.g., ion controller beams) in a trapped ion system, where the method includes applying a linear array of laser beams to respective ions in a linear array of ions in a trap, performing, in response to the laser beams being applied, parallel measurements on the ions, the parallel measurements including multiple, separate measurements on each of the ions to identify fluctuations in intensity in the respective laser beams at each ion, and adjusting the intensity of one or more of the laser beams in response to fluctuations being identified from the parallel measurements. A corresponding system for intensity stabilization of laser beams in a trapped ion system is also described.