Phase-stabilized UV light at 267 nm through twofold second harmonic generation

authored by: F. Dawel, S. Hannig, J. Kramer, C. Nauk, P. O. Schmidt, Benjamin Kraus
Abstract: Providing phase stable laser light is important to extend the interrogation time of optical clocks towards many seconds and thus achieve small statistical uncertainties. We report a laser system providing more than 50 µW phase-stabilized UV light at 267.4 nm for an aluminium ion optical clock. The light is generated by frequency-quadrupling a fibre laser at 1069.6 nm in two cascaded non-linear crystals, both in single-pass configuration. In the first stage, a 10 mm long PPLN waveguide crystal converts 1 W fundamental light to more than 0.2 W at 534.8 nm. In the following 50 mm long DKDP crystal, more than 50 µW of light at 267.4 nm are generated. An upper limit for the passive short-term phase stability has been measured by a beat-node measurement with an existing phase-stabilized quadrupling system employing the same source laser. The resulting fractional frequency instability of less than 5×10⁻¹⁷ after 1 s supports lifetime-limited probing of the ²⁷Al⁺ clock transition, given a sufficiently stable laser source. A further improved stability of the fourth harmonic light is expected through interferometric path length stabilisation of the pump light by back-reflecting it through the entire setup and correcting for frequency deviations. The in-loop error signal indicates an electronically limited instability of 1 × 10⁻¹⁸ at 1 s.
Organisation(s): Institute of Quantum Optics
QuantumFrontiers
CRC 1464: Relativistic and Quantum-Based Geodesy (TerraQ)
External Organisation(s): National Metrology Institute of Germany (PTB)
DLR-Institute for Satellite Geodesy and Inertial Sensing
German Aerospace Center (DLR)
Type: Article
Journal: Optics express
Volume: 30
Pages: 44992-45007
No. of pages: 16
ISSN: 1094-4087
Publication date: 05.12.2022
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Atomic and Molecular Physics, and Optics
Electronic version(s): https://doi.org/10.1364/OE.471450 (Access: Open)

BibTeX

@article{f4c3b6c9d11f4506a8be94fc70284eaf,
title = "Phase-stabilized UV light at 267 nm through twofold second harmonic generation",
abstract = "Providing phase stable laser light is important to extend the interrogation time of optical clocks towards many seconds and thus achieve small statistical uncertainties. We report a laser system providing more than 50 µW phase-stabilized UV light at 267.4 nm for an aluminium ion optical clock. The light is generated by frequency-quadrupling a fibre laser at 1069.6 nm in two cascaded non-linear crystals, both in single-pass configuration. In the first stage, a 10 mm long PPLN waveguide crystal converts 1 W fundamental light to more than 0.2 W at 534.8 nm. In the following 50 mm long DKDP crystal, more than 50 µW of light at 267.4 nm are generated. An upper limit for the passive short-term phase stability has been measured by a beat-node measurement with an existing phase-stabilized quadrupling system employing the same source laser. The resulting fractional frequency instability of less than 5×10−17 after 1 s supports lifetime-limited probing of the 27Al+ clock transition, given a sufficiently stable laser source. A further improved stability of the fourth harmonic light is expected through interferometric path length stabilisation of the pump light by back-reflecting it through the entire setup and correcting for frequency deviations. The in-loop error signal indicates an electronically limited instability of 1 × 10−18 at 1 s.",
author = "F. Dawel and S. Hannig and J. Kramer and C. Nauk and Schmidt, {P. O.} and Benjamin Kraus",
note = "Funding Information: Funding. Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) Project-ID (434617780 - SFB 1464); and under Germany{\textquoteright}s Excellence Strategy (EXC-2123 Quantum Frontiers–390837967); European Metrology Programme for Innovation and Research (EMPIR) cofinanced from the participating 5 states and European Union{\textquoteright}s Horizon 2020 Research and Innovation Programme (Project No. 20FUN01 TSCAC); State of Lower Saxony, Hannover, Germany, through Nieders{\"a}chsisches Vorab.",
year = "2022",
month = dec,
day = "5",
doi = "10.1364/OE.471450",
language = "English",
volume = "30",
pages = "44992--45007",
journal = "Optics express",
issn = "1094-4087",
publisher = "OSA - The Optical Society",
number = "25",
}