Optical Clock Networks – QuantumFrontiers – Leibniz Universität Hannover

Establish fiber-based optical clock networks, improve optical clocks and frequency transfer techniques, exploit chronometric levelling for geodesy.

Activities

Optical clocks:
- Bring the inaccuracy and instability stationary optical clocks below the level of 1 part in 1018
- Bring today’s optical clocks from prototype status to more reliable, rugged, transportable and miniaturized devices
- Investigate compound clocks
- Improve transportable Sr clock
- Test new Al+ logic clock
Frequency Transfer:
- Consolidate inaccuracy and instability of interferometric fibre links in the 10-19to 10-20 regime
- Investigate link non-reciprocality and relativistic effects
- Investigate coherent free-space frequency transfer
CRC 1464 TerraQ:
- Establish chronometric levelling with cm resolution as routine tool for geodesy
- Transfer lab-based link performance to robust in-field systems
- Identify locations and applications for chronometric levelling
Other:
- Coordinate measurement campaigns and results
- Investigate new network schemes

Competences/Services

Grosche: Frequency transfer techniques
Lisdat: Stationary and transportable Sr optical lattice clocks
Schmidt: Transportable Al+ clocks
Müller: Relativistic geodesy
Lämmerzahl: Relativistic geodesy

Scientific Output

Publications

Filzinger M, Dörscher S, Lange R, Klose J, Steinel M, Benkler E et al. Improved limits on the coupling of ultralight bosonic dark matter to photons from optical atomic clock comparisons. 2023 Jan 9.
doi.org/10.48550/arXiv.2301.03433

Bondza S, Lisdat C, Kroker S, Leopold T. Two-Color Grating Magneto-Optical Trap for Narrow-Line Laser Cooling. Physical review applied. 2022 Apr 1;17(4). 044002.
doi.org/10.1103/physrevapplied.17.044002

Herbers S, Häfner S, Dörscher S, Lücke T, Sterr U, Lisdat C. Transportable clock laser system with an instability of 1.6 × 10^-16. Optics letters. 2022 Okt 15;47(20):5441-5444.
doi.org/10.1364/OL.470984

Schioppo M, Kronjäger J, Silva A, Ilieva R, Paterson JW, Baynham CFA et al. Comparing ultrastable lasers at 7 × 10−17 fractional frequency instability through a 2220 km optical fibre network. Nature Communications. 2022 Jan 11;13(1). 212.
doi.org/10.1038/s41467-021-27884-3

Dörscher S, Huntemann N, Schwarz R, Lange R, Benkler E, Lipphardt B et al. Optical frequency ratio of a ¹⁷¹Yb⁺ single-ion clock and a ⁸⁷Sr lattice clock. METROLOGIA. 2021 Feb;58(1). 015005.
doi.org/10.1088/1681-7575/abc86f

Pelzer L, Dietze K, Kramer J, Dawel F, Krinner L, Spethmann N et al. Tailored optical clock transition in ⁴⁰Ca⁺. Measurement: Sensors. 2021 Dez;18. 100326.
doi.org/10.1016/j.measen.2021.100326

Micke P, Leopold T, King SA, Benkler E, Spieß LJ, Schmöger L et al. Coherent laser spectroscopy of highly charged ions using quantum logic. NATURE. 2020 Feb 6;578:60-65.
doi.org/10.48550/arXiv.2010.15984
,
doi.org/10.1038/s41586-020-1959-8

Porsev SG, Safronova UI, Safronova MS, Schmidt PO, Bondarev AI, Kozlov MG et al. Optical clocks based on the Cf¹⁵⁺ and Cf¹⁷⁺ ions. Physical Review A. 2020 Jul 6;102(1). 012802.
doi.org/10.48550/arXiv.2004.05978
,
doi.org/10.1103/PhysRevA.102.012802

Schulte M, Lisdat C, Schmidt PO, Sterr U, Hammerer K. Prospects and challenges for squeezing-enhanced optical atomic clocks. Nature Communications. 2020 Nov 24;11(1). 5955.
doi.org/10.1038/s41467-020-19403-7

Wu H, Müller J, Lämmerzahl C. Clock networks for height system unification: A simulation study. Geophysical journal international. 2018 Nov 28;216(3):1594-1607.
doi.org/10.1093/gji/ggy508

TG Members

Involved Members and their Relevant Expertise

Members	Institution	Relevant Expertise
Christian Lisdat, Leader	PTB	Sr Optical Lattice Clock
Gesine Grosche	PTB	Free-Space Frequency Transfer; Frequency Transfer Techniques
Alexander Kuhl	PTB	Free-Space Frequency Transfer
Chetan Vishwakarma	PTB	Sr Optical Lattice Clock
Jürgen Müller	LUH	Relativistic Geodesy; LLR Relativity Test; Application of Quantum Gravimetry
Piet O. Schmidt	PTB / LUH	Quantum Logic Spectroscopy of Highly Charged Ions; Al+ Clock
Stephan Hannig	PTB	Transportable Al+ Clock
Claus Lämmerzahl	ZARM	Quantum Sensors in Free Fall; Relativistic Geodesy; Quantum Objects in Gravity
Steffen Sauer	TUBS	Ultra-stable cavities for optical clocks
Tara Liebisch	PTB	Clock Network Schemes
Ernst M. Rasel	LUH	Quantum Gravimeters; Atom-Chip Based Gravimeters and Inertial Sensors
Stefanie Kroker	PTB /	Complex Coupled High Index Waveguide Arrays; Photonic Nanomaterials in the Strong Optomechanical Coupling Regime
Dennis Philipp	ZARM	General Relativity, relativistic geodesy
Eva Hackmann	ZARM	General Relativity, relativistic geodesy
Steffen Schön	IfE	GNSS Frequency Transfer
Sebastian Koke	PTB	Frequency Transfer Techniques
Jingxian Ji	PTB	Free-Space Frequency Transfer
Jaffar Kadum	PTB	Frequency Transfer, Fibre Brillouin Amplifiers
Akbar Shabanloui	LUH	Gravity field modelling, clock networks, height systems, precise satellite orbit determination





	PTB

All Topical Groups

FOUNDATIONS OF METROLOGY

APPLICATIONS IN METROLOGY

Back to Topical Groups overview