Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Optimization of an Injection Locked Laser System for Cold Neutral Atom Traps

Elliot M Lehman

Published Jan 1, 2019• 0 citations
OpenAlex

Abstract

Many types of quantum systems are being explored for use in quantum computers. One type of quantum system that shows promise for quantum computing is trapped neutral atoms. They have long coherence times, since they have multiple stable ground states and have minimal coupling with other atoms and their environment, and they can be trapped in arrays, making them individu- ally addressable. Once trapped, they can be initialized and operated on using laser pulses. This experiment utilizes a pinhole diffraction pattern, which can trap atoms in both bright and dark areas. To maximize trap strength, an injection-locked laser amplification system is used to provide a high-power, precisely tunable light source for the diffraction pattern. This amplification system depends on the coupling between a “seed” laser and a “receiving” laser. In previous analyses of the coupling between these two laser diodes, the effects on injection locking when varying temperature and current of both lasers have been shown to be highly nonlinear, and few general trends have been identified. In this project, in order to optimize and better characterize the system, automation of the data-taking and varying parameters was implemented. High efficiency lock zones of laser currents and temperatures were identified, and these locking zones will allow us to create strong atom traps for our experiment.

Related papers

Assembling and Characterizing the Efficiency of an Injection Locked Laser System for Cold Neutral Atom Optical Traps

Alexandra Papa Crawford

Creating a quantum computer requires a system of particles that can be well-controlled to achieve quantum operations. We need a large array of these particles – called qubits – with long coherence times, which can be initialized, operated on by single and two qubit gates, and read out. For neutral atoms, the qubit states are stable ground states that interact minimally with the environment, leading to long coherence times. Experimentally, the qubits are manipulated using carefully timed laser beam pulses with controlled frequency and intensity, but the outstanding issue for optically trapping cold atoms is finding a light pattern that can hold an array of individually addressable atoms to perform these quantum operations. To solve this, pinhole diffraction patterns were previously computationally analyzed to trap a 2D array of qubits within localized bright and dark spots. This project implements an injection locked laser into this system to provide a high power, tunable light source for the pinhole diffraction pattern atomic trap. In this project, the injection locked laser system is tuned to and analyzed at 780 nm to observe the locking efficiency as a function of the laser diode temperature or current supplied to the tuned-frequency laser diode, also known as the seed laser. Data taken on the injection lock efficiency over varying seed laser power in the system, current supplied to the seed laser diode, and laser diode temperature confirm that there is a large dependence upon each of these settings. An optimal combination of seed laser diode temperature and current supplied to it can be found to provide an efficient and stable power source for the atomic trap.

•Jan 1, 2018•0 citations

Developing an Imaging System to Monitor Atom Traps for Neutral Atom Quantum Computing

Jenna Valdez

Quantum computing exploits the laws of quantum mechanics to exponentially increase computing rate for certain processes. A realized quantum computer could break encryptions and simulate large quantum systems previously unbreakable and unattainable with classical computers. Neutral atom quantum computing is a viable candidate for building these devices that satisfies four of the five criteria for a successful quantum computer. We are exploring a novel method in creating neutral atom qubits that involves a magneto-optical trap and a dipole trap created in the diffraction pattern behind an array of pinholes. The magneto-optical trap works to cool the atoms and centralize them into a cold-atom cloud in an ultra-high vacuum chamber. Laser light is then projected into the chamber through the array of pinholes, trapping the cooled atoms in light traps. In order to test the efficiency of our trapping method, I have developed an imaging system that monitors the atoms. The system is comprised of a high-speed camera that takes images of the trap while a photodiode measures the fluorescence signal from the cold-atom cloud. These measurements are used to determine the number of atoms successfully trapped, how long they remain trapped, and the trap frequency. This paper presents the details and process of developing the complete imaging system.

•Jan 1, 2017•0 citations

Achieving Laser Wavelength Stability for Use in Neutral Atom Quantum Computing

Jennifer H. Rushing

Quantum computing may still be decades away from realization but the pieces necessary for the construction of the first quantum chip are beginning to come together. One piece still eluding researchers is the ability to address individual atoms within a scalable quantum chip structure. The resolution to this issue may be found in any one of several promising implementations, including the use of neutral atoms trapped in 2D optical lattices. One method of constructing such lattices, which has been shown to be computationally viable, employs the diffraction pattern just behind a circular aperture. Laser wavelength stability plays a crucial role in this approach, which entails constructing a 2D optical lattice with an array of pinholes, populating the lattice with atoms collected by a magneto optical trap (MOT), and manipulating the atoms trapped within the lattice structure for quantum computations. Experimental work was done toward achieving the laser wavelength stability required for these tasks. First, we investigated inadequate temperature control of the laser diodes and a thermal mass issue attributed to the laser mounts was resolved. We proceeded to analyze the electronics of the laser locking feedback system, which were failing to hold the lasers steady at a desired wavelength. Several noise sources contributing to signal instability were identified and eliminated, but drifting of the error signal was persistent. A subsequent fix was then made to the locking electronics and sufficient laser wavelength stability was demonstrated when atoms were trapped for the first time in the Cal Poly MOT on September 2, 2011.

•Jan 1, 2011•0 citations

Polarization-dependent atomic dipole traps behind a circular aperture for neutral-atom quantum computing

Katharina Gillen-Christandl, Bert Copsey

The neutral-atom quantum computing community has successfully implemented almost all necessary steps for constructing a neutral-atom quantum computer. We present computational results of a study aimed at solving the remaining problem of creating a quantum memory with individually addressable sites for quantum computing. The basis of this quantum memory is the diffraction pattern formed by laser light incident on a circular aperture. Very close to the aperture, the diffraction pattern has localized bright and dark spots that can serve as red-detuned or blue-detuned atomic dipole traps. These traps are suitable for quantum computing even for moderate laser powers. In particular, for moderate laser intensities ($~100$ W/${\mathrm{cm}}^{2}$) and comparatively small detunings ($~1000$--10 000 linewidths), trap depths of $~1$ mK and trap frequencies of several to tens of kilohertz are achieved. Our results indicate that these dipole traps can be moved by tilting the incident laser beams without significantly changing the trap properties. We also explored the polarization dependence of these dipole traps. We developed a code that calculates the trapping potential energy for any magnetic substate of any hyperfine ground state of any alkali-metal atom for any laser detuning much smaller than the fine-structure splitting for any given electric field distribution. We describe details of our calculations and include a summary of different notations and conventions for the reduced matrix element and how to convert it to SI units. We applied this code to these traps and found a method for bringing two traps together and apart controllably without expelling the atoms from the trap and without significant tunneling probability between the traps. This approach can be scaled up to a two-dimensional array of many pinholes, forming a quantum memory with single-site addressability, in which pairs of atoms can be brought together and apart for two-qubit gates for quantum computing.

Physical Review A•Feb 9, 2011•13 citations

An Injection-locked Diode Laser for Cold Rydberg Atom Experiments

Margaret S. Martei, Anders Wood, Duncan Tate

A free-running, temperature stabilized diode laser has been injection-locked to an external cavity diode laser for use in cold Rydberg atom experiments. Cold rubidium atoms in a magneto-optical trap (MOT) are excited to Rydberg states using a 10 ns laser pulse. The Rydberg atoms spontaneously ionize due to dipole forces, and the collisional ionization dynamics are observed as a function of atom density and principal quantum number of the Rydberg state, n. The injection-locked diode laser will be used as a repumper in conjunction with a dark spontaneous-force optical trap (SPOT) to increase the Rydberg state density. We report on the design of the injection-locked laser system.

•Jan 1, 2007•0 citations

Investigating the Talbot Effect in Arrays of Optical Dipole Traps for Neutral Atom Quantum Computing

Sergio Aguayo

Quantum computers are devices that are able to perform calculations not achievable for classical computers. Although there are many methods for creating a quantum computer, using neutral atoms offers the advantage of being stable when compared to other methods. The purpose of this investigation is to explore possible optical dipole trap configurations that would be useful for implementing a quantum computer with neutral atoms. Specifically, we computationally investigate arrays of pinholes, the diffraction pattern generated by them, and the onset of the Talbot effect in these traps. We manipulate the radius of the pinholes, the number of pinholes in the array, and the distance between adjacent pinholes in order to create trap configurations where the presence/absence of the Talbot effect contributes to the usefulness of the trap for quantum computing. We find configurations with pinhole distances of 80 μm and 100/110 μm respectively satisfied an absence and a strong presence of the Talbot effect.

•Jan 1, 2019•0 citations
Many types of quantum systems are being explored for use in quantum computers. One type of quantum system that shows promise for quantum computing is trapped neutral atoms. They have long coherence times, since they have multiple stable ground states and have minimal coupling with other atoms and their environment, and they can be trapped in arrays, making them individu- ally addressable. Once trapped, they can be initialized and operated on using laser pulses. This experiment utilizes a pinhole diffraction pattern, which can trap atoms in both bright and dark areas. To maximize trap strength, an injection-locked laser amplification system is used to provide a high-power, precisely tunable light source for the diffraction pattern. This amplification system depends on the coupling between a “seed” laser and a “receiving” laser. In previous analyses of the coupling between these two laser diodes, the effects on injection locking when varying temperature and current of both lasers have been shown to be highly nonlinear, and few general trends have been identified. In this project, in order to optimize and better characterize the system, automation of the data-taking and varying parameters was implemented. High efficiency lock zones of laser currents and temperatures were identified, and these locking zones will allow us to create strong atom traps for our experiment.
Creating a quantum computer requires a system of particles that can be well-controlled to achieve quantum operations. We need a large array of these particles – called qubits – with long coherence times, which can be initialized, operated on by single and two qubit gates, and read out. For neutral atoms, the qubit states are stable ground states that interact minimally with the environment, leading to long coherence times. Experimentally, the qubits are manipulated using carefully timed laser beam pulses with controlled frequency and intensity, but the outstanding issue for optically trapping cold atoms is finding a light pattern that can hold an array of individually addressable atoms to perform these quantum operations. To solve this, pinhole diffraction patterns were previously computationally analyzed to trap a 2D array of qubits within localized bright and dark spots. This project implements an injection locked laser into this system to provide a high power, tunable light source for the pinhole diffraction pattern atomic trap. In this project, the injection locked laser system is tuned to and analyzed at 780 nm to observe the locking efficiency as a function of the laser diode temperature or current supplied to the tuned-frequency laser diode, also known as the seed laser. Data taken on the injection lock efficiency over varying seed laser power in the system, current supplied to the seed laser diode, and laser diode temperature confirm that there is a large dependence upon each of these settings. An optimal combination of seed laser diode temperature and current supplied to it can be found to provide an efficient and stable power source for the atomic trap.
Quantum computing exploits the laws of quantum mechanics to exponentially increase computing rate for certain processes. A realized quantum computer could break encryptions and simulate large quantum systems previously unbreakable and unattainable with classical computers. Neutral atom quantum computing is a viable candidate for building these devices that satisfies four of the five criteria for a successful quantum computer. We are exploring a novel method in creating neutral atom qubits that involves a magneto-optical trap and a dipole trap created in the diffraction pattern behind an array of pinholes. The magneto-optical trap works to cool the atoms and centralize them into a cold-atom cloud in an ultra-high vacuum chamber. Laser light is then projected into the chamber through the array of pinholes, trapping the cooled atoms in light traps. In order to test the efficiency of our trapping method, I have developed an imaging system that monitors the atoms. The system is comprised of a high-speed camera that takes images of the trap while a photodiode measures the fluorescence signal from the cold-atom cloud. These measurements are used to determine the number of atoms successfully trapped, how long they remain trapped, and the trap frequency. This paper presents the details and process of developing the complete imaging system.
Quantum computing may still be decades away from realization but the pieces necessary for the construction of the first quantum chip are beginning to come together. One piece still eluding researchers is the ability to address individual atoms within a scalable quantum chip structure. The resolution to this issue may be found in any one of several promising implementations, including the use of neutral atoms trapped in 2D optical lattices. One method of constructing such lattices, which has been shown to be computationally viable, employs the diffraction pattern just behind a circular aperture. Laser wavelength stability plays a crucial role in this approach, which entails constructing a 2D optical lattice with an array of pinholes, populating the lattice with atoms collected by a magneto optical trap (MOT), and manipulating the atoms trapped within the lattice structure for quantum computations. Experimental work was done toward achieving the laser wavelength stability required for these tasks. First, we investigated inadequate temperature control of the laser diodes and a thermal mass issue attributed to the laser mounts was resolved. We proceeded to analyze the electronics of the laser locking feedback system, which were failing to hold the lasers steady at a desired wavelength. Several noise sources contributing to signal instability were identified and eliminated, but drifting of the error signal was persistent. A subsequent fix was then made to the locking electronics and sufficient laser wavelength stability was demonstrated when atoms were trapped for the first time in the Cal Poly MOT on September 2, 2011.
The neutral-atom quantum computing community has successfully implemented almost all necessary steps for constructing a neutral-atom quantum computer. We present computational results of a study aimed at solving the remaining problem of creating a quantum memory with individually addressable sites for quantum computing. The basis of this quantum memory is the diffraction pattern formed by laser light incident on a circular aperture. Very close to the aperture, the diffraction pattern has localized bright and dark spots that can serve as red-detuned or blue-detuned atomic dipole traps. These traps are suitable for quantum computing even for moderate laser powers. In particular, for moderate laser intensities ( 100~100 100 W/cm2{\mathrm{cm}}^{2}cm2) and comparatively small detunings ( 1000~1000 1000--10 000 linewidths), trap depths of  1~1 1 mK and trap frequencies of several to tens of kilohertz are achieved. Our results indicate that these dipole traps can be moved by tilting the incident laser beams without significantly changing the trap properties. We also explored the polarization dependence of these dipole traps. We developed a code that calculates the trapping potential energy for any magnetic substate of any hyperfine ground state of any alkali-metal atom for any laser detuning much smaller than the fine-structure splitting for any given electric field distribution. We describe details of our calculations and include a summary of different notations and conventions for the reduced matrix element and how to convert it to SI units. We applied this code to these traps and found a method for bringing two traps together and apart controllably without expelling the atoms from the trap and without significant tunneling probability between the traps. This approach can be scaled up to a two-dimensional array of many pinholes, forming a quantum memory with single-site addressability, in which pairs of atoms can be brought together and apart for two-qubit gates for quantum computing.
A free-running, temperature stabilized diode laser has been injection-locked to an external cavity diode laser for use in cold Rydberg atom experiments. Cold rubidium atoms in a magneto-optical trap (MOT) are excited to Rydberg states using a 10 ns laser pulse. The Rydberg atoms spontaneously ionize due to dipole forces, and the collisional ionization dynamics are observed as a function of atom density and principal quantum number of the Rydberg state, n. The injection-locked diode laser will be used as a repumper in conjunction with a dark spontaneous-force optical trap (SPOT) to increase the Rydberg state density. We report on the design of the injection-locked laser system.
Quantum computers are devices that are able to perform calculations not achievable for classical computers. Although there are many methods for creating a quantum computer, using neutral atoms offers the advantage of being stable when compared to other methods. The purpose of this investigation is to explore possible optical dipole trap configurations that would be useful for implementing a quantum computer with neutral atoms. Specifically, we computationally investigate arrays of pinholes, the diffraction pattern generated by them, and the onset of the Talbot effect in these traps. We manipulate the radius of the pinholes, the number of pinholes in the array, and the distance between adjacent pinholes in order to create trap configurations where the presence/absence of the Talbot effect contributes to the usefulness of the trap for quantum computing. We find configurations with pinhole distances of 80 μm and 100/110 μm respectively satisfied an absence and a strong presence of the Talbot effect.