News and Blog

Towards Nuclear Quantum Optics: Thorsten Schumm visits Tulon Photonics 

On 11-June 2024, Thorsten Schumm gave a talk at the Institute of Science and Technology, Austria about his historic work on nuclear laser excitation. Thorsten visited Onur Hosten’s Quantum Sensing group, along with the Tulon Photonics spin-off founders. Tulon Photonics is proud to have Thorsten Schumm in its scientific advisory board. 

Thorsten heads the monumental endeavor of peering into the nucleus with a laser.  For the first time in history, the nucleus of an atom has been excited with a laser. Nuclear excited states are typically highly energetic, hence the only way to access them is by gamma rays or colliders such as at the LHC-CERN. 

To achieve this requires hunting for an atomic species with a low energy nuclear excitation. One that is low enough to be accessed by a laser. Out of all possible candidates, Thorium-229 presented the lowest possible nuclear excitable transition of ~ 8 eV. In optics, this would correspond to ~ 150 nm in wavelength.  This color corresponds to Vacuum Ultraviolet light (VUV). Rightly so, since even air absorbs VUV, thereby, vacuum environments are required for VUV light.  On the other hand, VUV laser light generation is in itself very difficult. 

To add to that difficulty, trapping the Thorium-229 isotopes in a host structure to allow optical interrogation is even more difficult.  To achieve this goal, the Thorium Nuclear Clock collaboration trapped Thorium-229 within CaF2 crystal. Calcium Flouride provides a perfect host for the Thorium atoms, as it is optically transparent.  In parallel to this, the VUV light is generated by 4-wave mixing; Three beams combine to create the 4th VUV laser beam.  

After more than a decade, Thorsten and his collaborators succeeded in exciting the nucleus of a Thorium-229 with a laser. This work pushes humanity towards the age of Nuclear Clocks. Nuclear clocks are 4-orders more accurate than optical atomic clocks.  It will also open up a new field of physics, Nuclear Quantum Optics.  To read more about this amazing work and its huge impact, check out the paper and links below.

Laser Excitation of the Th-229 Nucleus

J. Tiedau, M. V. Okhapkin, K. Zhang, J. Thielking, G. Zitzer, E. Peik, F. Schaden, T. Pronebner, I. Morawetz, L. Toscani De Col, F. Schneider, A. Leitner, M. Pressler, G. A. Kazakov, K. Beeks, T. Sikorsky, and T. Schumm

Phys. Rev. Lett. 132, 182501 – Published 29 April 2024

Shedding Light on the Thorium-229 Nuclear Clock Isomer

Peter Thirolf

Department of Physics, Ludwig-Maximilians-Universität München, Munich, Germany

April 29, 2024• Physics 17, 71

Thorsten’s Quantum Metrology at TU Wien webpage:

Thorium Nuclear Clock

Published: 11-June-2024

Sensing and controlling torsional motion: a new paper from the Hosten group

A new paper from Onur Hosten’s Quantum Sensing with Light and Atoms research group at IST-Austria was published a few months ago.  The paper describes a proposed cavity optomechanics experiment for Quantum Sensing applications.  To quote the paper:

“…... we anticipate development of precision torque sensors utilizing torsional pendulums that can support sensitivities below 10-19 Nm/√Hz, while the motion of the pendulums are dominated by quantum radiation pressure noise at sub-microwatts of incoming laser power. These developments will provide horizons for experiments at the interface of quantum mechanics and gravity. “

The project aims to answer the most fundamental question in physics in the 21st century: the nature of gravity and its connection to quantum theory. This is the core question that Onur Hosten aims at exploring with his ERC consolidator grant. Historically, such fundamental physics experiments were at a larger scale involving personnel in the 100s. Onur Hosten’s research endeavor is one of a few (but growing in number) pioneering table-top experiments operated by a small team pushing the boundaries of engineering and instrumentation.

The optical cavity used in the setup utilizes Tulon Photonics’ IP, SquashLock. SquashLock is ideal in this case as it minimizes the need for modulators and extra electronics.  Laser-Cavity locking is achieved with top performance and being minimalistic as a consequence. For more information, you can access the paper through information below. Or better yet, feel free to contact the authors.  Whether you’re a physicist, engineer, or a young curious student, Tulon Photonics and the Onur Hosten research group are happy to answer any questions from anyone and everyone.

Zigzag optical cavity for sensing and controlling torsional motion

Sofia Agafonova, Umang Mishra, Fritz Diorico, and Onur Hosten

Phys. Rev. Research 6, 013141 – Published 5 February 2024

Hosten Group IST-Austria webpage:

Published: 24-May-2024

Our paper on Tulon Photonics' core IP, SquashLock is out. This work is several years in the making delayed only by IP protection. Tulon Photonics will bring this new laser technology to our modern industry pushing forth a new age of photonics.

(Photo): Optica's promotion on Linkedin

Our 2nd laser technology paper is out. This is one of the building blocks of Tulon photonics' IP and patents.

Arxiv version:

The original SquashLock can be found here.

Tulon Photonics featured in Austria's Brutkasten

Tulon Photonics along with the other FFG spin-off recipients were featured recently in Brutkasten, a Austria local news outlet. Tulon Photonics' founder, Fritz Diorico gave a 2 minute pitch during the FFG demo day early May.

Aisling represents Tulon Photonics at Wilhelm Exner Medal Foundation

Aisling represented Tulon Photonics with a Poster at the Wilhelm Exner awarding event held and organized by Österreichischer Gewerbeverein (Austrian Trade Association) this last 22-23 May 2023. She won 2nd place in start-up category. 

Congratulations Aisling! We are very proud of you!

For more info, check the link below.

Onur Hosten featured in Austrian news.

Onur Hosten, the chief scientific adviser of Tulon Photonics, was recently featured in Austrian news.  Onur is the co-inventor of the Tulon Photonics core IP.  He initiated the idea of modulation-free laser frequency stabilization, to which he and Fritz religiously applied in various cases during the Pandemic.

To read the original news article, ERC news and more about Onur's work, check below. 

New Article:

Onur Hosten from the Institute of Science and Technology Austria tackles the really big questions: How does gravity behave in the quantum realm? Check it out!  

 QUANTENGRAVITATION Neuer Versuch, Quantenphysik und Relativitätstheorie zu vereinen

ERC News:

The European Research Council (ERC) has selected the proposals of four ISTA scientists for #funding with two million Euros each.

Onur Hosten's Research Group at ISTA

FFG Demo Day

Fritz Diorico presents at the FFG Demo day last 10 May 2023 in front of a wide audience including Henrietta Egerth-Stadlhuber, Managing Director of FFG and Martin Polaschek, Federal Minister for Education, Science and Research.  

More information: