A self-injection locked DBR laser for laser cooling of beryllium ions

King, Simon; Leopold, Tobias; Thekkeppatt, Premjith; Schmidt, Piet O.

doi:10.1007/s00340-018-7080-0

Cited by 10 publications

(5 citation statements)

References 50 publications

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“…A repumping laser couples the 9 Be + 2 S1/2 and 2 P1/2 levels (not shown in Fig. 2a) for electronic state preparation and for depopulation of state |↑⟩L 36 . The Ar 13+…”

Section: Ground-state Cooling and Quantum Logicmentioning

confidence: 99%

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Coherent laser spectroscopy of highly charged ions using quantum logic

Micke

Leopold

King

et al. 2020

Nature

134

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Precision spectroscopy of atomic systems 1 is an invaluable tool for the advancement of our understanding of fundamental interactions and symmetries 2. Recently, highly charged ions (HCI) have been proposed for sensitive tests of physics beyond the Standard Model 2-5 and as candidates for high-accuracy atomic clocks 3,5. However, the implementation of these ideas has been hindered by the parts-per-million level spectroscopic accuracies achieved to date 6-8. Here, we cool a trapped HCI to the lowest reported temperatures, and introduce coherent laser spectroscopy on HCI with an eight orders of magnitude leap in precision. We probe the forbidden optical transition in 40 Ar 13+ at 441 nm using quantum-logic spectroscopy 9,10 and measure both its excited-state lifetime and g-factor. Our work ultimately unlocks the potential of HCI, a large, ubiquitous atomic class, for quantum information processing, novel frequency standards, and highly sensitive tests of fundamental physics, such as searching for dark matter candidates 11 or violations of fundamental symmetries 2. Alike a microscope aimed at the quantum world, laser spectroscopy pursues ever higher resolving power. Every increase in resolution enables deeper insights into the subtle effects that all known fundamental interactions have on the atomic wave function. Advances in optical frequency metrology have dramatically improved resolution in the last three decades 1 , and are making laser spectroscopy an extremely sensitive tool for studying open physics questions such as the nature of dark matter, the strength of parity violation, or a possible violation of Einstein's theory of relativity 2. However, only a few atomic and ionic species are currently within the reach of cutting-edge optical frequency metrology. Expanding this field of exploration to systems with high sensitivity to such effects is therefore crucial. Due to their extreme properties, highly charged ions (HCI) are promising candidates for such fundamental tests. Contributions from special

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“…A repumping laser couples the 9 Be + 2 S1/2 and 2 P1/2 levels (not shown in Fig. 2a) for electronic state preparation and for depopulation of state |↑⟩L 36 . The Ar 13+…”

Section: Ground-state Cooling and Quantum Logicmentioning

confidence: 99%

“…A repumping laser couples the 9 Be + 2 S1/2 and 2 P1/2 levels (not shown in Fig. 2a) for electronic state preparation and for depopulation of state |↑⟩L 36 . The Ar 13+ Zeeman ground state is then deterministically prepared with clock laser sideband pulses (see Extended Data Fig.…”

Section: Ground-state Cooling and Quantum Logicmentioning

confidence: 99%

Coherent laser spectroscopy of highly charged ions using quantum logic

Micke

Leopold

King

et al. 2020

Nature

134

View full text Add to dashboard Cite

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“…However, 313 nm light, generated via frequencydoubling, had a power level of only 5-7 mW [121]. It has been demonstrated, that a distributed Bragg reflector (DBR) ridge waveguide laser diode, cooled to moderate 5.6 • C but still below the dew point, can generate 626 nm light [122]. The 626 nm output power of that system is not sufficient to generate enough 313 nm light for Doppler cooling while simultaneously allow for locking it to an atomic reference, which is a crucial requirement for keeping it at the desired cooling frequency.…”

Section: Doppler Cooling Lasermentioning

confidence: 99%

“…The 626 nm output power of that system is not sufficient to generate enough 313 nm light for Doppler cooling while simultaneously allow for locking it to an atomic reference, which is a crucial requirement for keeping it at the desired cooling frequency. Although this is no fundamental limit, as amplification through a tapered amplifier at 626 nm can potentially alleviate this limitation [122]. While Doppler cooling is certainly possible with those two systems, the technologies seem not mature enough for our purpose and the convenience of having up to 120 mW of UV power available, as our laser system provides, can't be denied.…”

Section: Doppler Cooling Lasermentioning

confidence: 99%

Ultra-low-vibration closed-cycle cryogenic surface-electrode ion trap apparatus

Dubielzig

Halama

Hahn

et al. 2021

Review of Scientific Instruments

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Trapped ions are one of the leading platforms for building scalable quantum information processors. Current ion traps run on less than 100 qubits. A useful quantum computer needs to operate thousands or even millions of qubits. If systems reach gate fidelities that allow for quantum error correction, gate errors below the physical fidelity can be reached, which is important for scaling. The most promising platform for scaling up ion-based quantum computers are surface electrode traps in connection with the so-called QCCD (Quantum Charge Coupled Device) architecture. In an evolution of the standard (laser-based) approach to quantum logic gates, gates can be performed by applying an oscillating magnetic near-field gradient to the ions. Current fidelities are about one order of magnitude away from reaching the fault tolerant threshold with no fundamental limitations in sight. Scaling QCCDs is impeded by heating rates of the ions as well as vacuum quality. Ions have to be stored for at least as long as it takes for an algorithm to run and subsequent readout. Collisions with background gas and heating can expel ions from the trap. The microwave near-field approach of driving gates benefits from ions that are trapped close to the trap surface. Unfortunately, heating becomes more prominent near the surface. A cryogenic environment reduces the background pressure by several orders of magnitude and the kinetic energy of gas molecules by two orders of magnitude. Heating rates in a cryogenic trap are about two orders of magnitude lower than in a room temperature trap with otherwise equal physical properties. To operate a QCCD processor, it is required to employ phase-stable Raman laser beams. The cryogenic design of the apparatus needs to take into account the resulting requirements for ultra-low vibration amplitudes. This is particularly relevant for closed-cycle cooling systems, which are desirable from an economic point of view compared to liquid cryostats that boil off helium, but which also feature moving mechanical parts that can introduce a serious amount of vibrations. Here, we present a vibration isolated closed cycle Gifford-McMahon cryocooler with record low vibration amplitudes of 29 nm (RMS=7.8 nm) in the vertical and 51 nm (RMS=13.5 nm) in the horizontal direction. It contains a self-sustained inner vacuum chamber that houses the trap. It features 100 DC connections, 10 of which are able to carry up to 1 A of current and 8 high frequency lines. At 5 K, we can apply continuous 3.4 W of microwave power continuously at 1 GHz to the trap electrodes without heating the system. This is about 5.8 times more than state of the art near-field gates require. We also present the laser systems required to for single-shot ablation loading and Doppler cooling of 9 Be + ions: a 70 mW 313 nm Dopper cooling laser, a 1064 nm ns-pulse laser for ablation of neutral beryllium atoms and a 235 nm laser for ionizing them. The detection system features an in vacuum imaging system on a cryogenic 3D translation stage that is able to scan...

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“…For a single ion cooled to the motional ground state, carrier (first blue sideband) π-times of approximately 13 (15) µs and 5 (23) µs in the axial and radial directions respectively are achieved with 1 mW of light per beam focused to a waist of 40 µm. The laser systems were set up following reference [56], except the repumper laser which is based on a frequency doubled DBR diode laser [60]. To ensure long-term alignment of the laser beams onto the ion, all 313 nm beams are delivered to the trap through hydrogen-loaded, large mode area optical fibres which have a typical transmission of 50 % for 1.5 m length [61,62].…”

Section: Loading and Cooling Ofmentioning

confidence: 99%

A cryogenic radio-frequency ion trap for quantum logic spectroscopy of highly charged ions

Leopold

King

Micke

et al. 2019

Review of Scientific Instruments

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A cryogenic radio-frequency ion trap system designed for quantum logic spectroscopy of highly charged ions is presented. It includes a segmented linear Paul trap, an in-vacuum imaging lens and a helical resonator. We demonstrate ground state cooling of all three modes of motion of a single 9 Be + ion and determine their heating rates as well as excess axial micromotion. The trap shows one of the lowest levels of electric field noise published to date. We investigate the magnetic-field noise suppression in cryogenic shields made from segmented copper, the resulting magnetic field stability at the ion position and the resulting coherence time. Using this trap in conjunction with an electron beam ion trap and a deceleration beamline, we have been able to trap single highly charged Ar 13+ (Ar XIV) ions concurrently with single Be + ions, a key prerequisite for the first quantum logic spectroscopy of a highly charged ion.

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A self-injection locked DBR laser for laser cooling of beryllium ions

Cited by 10 publications

References 50 publications

Coherent laser spectroscopy of highly charged ions using quantum logic

Coherent laser spectroscopy of highly charged ions using quantum logic

Ultra-low-vibration closed-cycle cryogenic surface-electrode ion trap apparatus

A cryogenic radio-frequency ion trap for quantum logic spectroscopy of highly charged ions

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