This work presents a stable and reliable turnkey continuous-wave laser system for a Yb/Ba multi-species trapped-ion quantum computer. The compact and rack-mountable optics system exhibits high robustness, operating over a year without realignment, regardless of temperature changes in the laboratory. The overall optical system is divided into a few isolated modules interconnected by optical fibers for easy maintenance. The light sources are frequency-stabilized by comparing their frequency with two complementary references, a commercial Fizeau wavelength meter and a high-finesse optical cavity. This scheme enables automatic frequency-stabilization for days with a sub-MHz precision.
This work presents a stable and reliable turnkey continuous-wave laser system for a Yb/Ba multi-species trapped-ion quantum computer. The compact and rack-mountable optics system exhibits high robustness, operating over a year without realignment, regardless of temperature changes in the laboratory. The overall optical system is divided into a few isolated modules interconnected by optical fibers for easy maintenance. The light sources are frequency-stabilized by comparing their frequency with two complementary references, a commercial Fizeau wavelength meter and a high-finesse optical cavity. This scheme enables automatic frequency-stabilization for days with a sub-MHz precision.
Robust laser delivery and stabilization are key components in atom-based quantum technologies, such as quantum computing. Moving these technologies towards product-like deployment requires scalable, compact, cost-effective, and upgradable modules. Here we describe laser systems consisting of application-flexible modules and demonstrate their performance by characterizing key metrics and by integration with ion trap systems. The laser system is confined to a single server rack and a compact locking station. Both are Class 1 laser products with fiber in-out and electronic control of the laser light. This is achieved through precision manufacture of optical boards that are designed to reduce the degrees of freedom, ease alignment, and increase the robustness to environmental factors. We present a range of 13 wavelengths from 375 nm to 1092 nm: efficiencies from laser source to ion trap range from 21 - 28%, with laser stabilization line widths below 1 MHz.
We present the design of a compact optical clock based on the 2 S 1/2 → 2 D 3/2 435.5 nm transition in 171 Yb + . The ion trap will be based on a micro-fabricated circuit, with surface electrodes generating a trapping potential to localize a single Yb ion a few hundred μ m from the electrodes. We present our trap design as well as simulations of the resulting trapping pseudo-potential. We also present a compact, multi-channel wavelength meter that will permit the frequency stabilization of the cooling, repumping and clear-out lasers at 369.5 nm, 935.2 nm and 638.6 nm needed to cool the ion. We use this wavelength meter to characterize and stabilize the frequency of extended cavity diode lasers at 369.5 nm and 638.6 nm.
This project sets out to frequency stabilize external cavity diode lasers of wavelengths λ = 935 nm and 739 nm, with an eye to Ytterbium-171 ion trapping.The desired laser linewidths were below 1 MHz at 1 second observation time and the desired long term frequency drifts were below a megahertz over the course of a few hours.To stabilize the lasers, two Pound-Drever-Hall laser frequency stabilisation systems were designed, constructed and characterized.The optical frequency references used were sub-megahertz linewidth optical cavities with Invar spacers.These cavities were designed and constructed inhouse.The achieved long term stability of the stabilized lasers was 1 MHz/h over a 5 hour measurement period.The laser frequency long term stabilities are limited by the thermal stabilities of the cavity spacers.The post stabilisation laser frequency noise was lowered when compared to the free running lasers.This was observed by determining the laser frequency noise power spectral densities.From the frequency noise power spectral densities lower bounds on the locked laser linewidths were established.This lower bound is 11.92 kHz for the 739 nm wavelength laser at 1 second observation time and 5.4 kHz for the 935 nm wavelength laser.An additional system was designed and constructed ii
We report on a laser-frequency-stabilization and phase-noise-filtering scheme at 871 nm for high-quality quantum operations with an optical 2S1/2--2D3/2 qubit in the 171Yb+ ion. The phase noise of the laser field in a frequency range close to the trapped ion's secular frequencies (0.5--2 MHz) causes undesirable excitations and thus reduces the fidelities of both single- and two-qubit gates. The most common way to overcome this problem is to filter this noise by passing the laser light through a cavity that suppresses high-frequency phase noise and provides a pure laser spectrum. Usually, the same cavity also serves as a reference for long-term frequency stabilization. We propose and characterize an improved laser-stabilization scheme consisting of (i) a reference laser locked to a high-finesse optical cavity providing a narrow linewidth and long-term frequency stability and (ii) a main laser locked to a tunable medium-finesse cavity for phase-noise filtering. The phase locking of the medium-finesse cavity resonance to the reference laser transfers its long-term stability to the main laser. This approach allows independent optimization of both the phase-noise filtering and long-term frequency-stabilization processes, as well as ensuring the robustness of the setup. The resulting laser spectrum is characterized by direct spectroscopy of an 171Yb+ ion in a linear Paul trap. We estimate the expected two-qubit gate infidelity with the filtered laser field to be well below 1%.
Quantum technologies are nowadays emerging as enabling tools for practical applications, such as quantum sensing, quantum computing and quantum metrology. Lasers play a central role in many of these technological platforms, e.g. for atomic clocks, ion-based or neutral atom-based quantum computers or atom interferometers. Here we present a complete laser system to cool, trap and control strontium atoms in an optical lattice or in tweezer arrays. A sub-Hz linewidth master laser, locked to a high-finesse optical cavity provides the frequency reference for an ultra-low noise comb. The rack-mounted laser system consists of all cooling, repumping, and clock lasers stabilized to the optical frequency comb. Each of the involved laser frequencies can therefore be tuned and mapped in the frequency domain with a high degree of stability. The system is controlled via a software interface, allowing to operate the cold-atom-based physics package autonomously. The system is tailored for the operation of 88Sr or 87Sr optical lattice clocks, or for quantum computing applications, but other sub-Hz lasers could be obtained by phase locking additional clock laser frequencies to the ultra-stable comb, enabling convenient and accurate optical frequency ratio measurements. The laser system architecture and the relevant characterization measurements will be presented, proposing some user-cases such as quantum computing and atom interferometry on strontium atoms. This represents a technological leap for quantum optics, allowing to explore further applications of quantum sensors outside a traditional lab.
Quantum information processing (QIP) approach based on trapped ions is a promising technology that exploits different ion species as individual qubits and qubit gates, while featuring long coherence times, high fidelity of operations, fast readout, and ion-ion gate entanglement. The practical usefulness of trapped-ion quantum computer depends on its further scaling to a large number of qubits. Meanwhile, trapped-ion quantum computer relies on a set of single-frequency lasers, utilizing them for different functions such as photoionization, atom cooling, optical pumping and qubit operations. Thus, a combination of narrow linewidth lasers is required, with the emission wavelengths precisely defined by the corresponding electronic transitions of the selected ion species. Further development, scalability and commercialization of quantum information technologies is interwind with the availability of affordable and robust single-frequency lasers on a variety of application-specific wavelengths. QIP manifests strict requirements posed to lasers in terms of central wavelength, linewidth, long-term stability, beam quality, polarization extinction ratio, side-mode suppression ratio, etc. In this work we present the development and characterization of multiwavelength narrow linewidth system designed for the Ba+ trapped ion computing. The laser system emits single-frequency, sub-MHz emission at 553 nm, 493 nm and 614 nm based on second-harmonic generation of two separate semiconductor laser platforms. Two-step photoionization of neutral Ba is implemented resonantly through 6s2 1S0 → 6s6p 1P1 transition corresponding to 553 nm wavelength, whereas Ba ion is Doppler cooled on 6S1/2 →6P1/2 transition corresponding to 493 nm. Such single-frequency greenyellow and cyan lasers are based on intracavity frequency doubled vertical-external-cavity surface-emitting laser (VECSEL), serving as an effective replacement of the legacy dye laser, previously used to address these Ba transition. On the other hand, frequency doubled external cavity diode laser (ECDL) is employed to generate 614 nm orange emission needed for 5D5/2→ 6P3/2 transition. The laser system incorporates modular laser engines together with low-noise driving electronics, mechanical and acoustic concealment and provide laser locking interfaces to high-finesse optical cavity or a wavemeter.