Continuously emitting superradiant laser utilizing intercombination lines of calcium
Final Report Abstract
Superradiant lasers are lasers that operate with an enhancement resonator whose bandwidth is significantly larger than the bandwidth of the laser transition used, so that the coherence resulting from the laser process is almost exclusively stored in the inverted laser medium. Such lasers can have emission line widths in the sub-millihertz range and are therefore particularly suitable for reading out ultra-stable atomic clocks. The objective of this proposal was twofold. 1. Based upon our recent successful demonstration of pulsed superradiant lasing using the 1S0 → 3P1 -intercombination transition of calcium at 657 nm with 370 Hz natural line width, we planned to demonstrate the realization of continuous operation, as an central step towards application of this new laser concept for time metrology. 2. We furthermore planned to demonstrate (pulsed and continuous) superradiant lasing using the far more narrow 1S0 → 3P0 -intercombination transition, whose line width can be tuned by a static magnetic field of a few Gauss in the sub-Hertz range. Unfortunately, our experiments showed that, while the short pulse regime operated well, these new tasks required extensive improvements with regard to the stability and efficiency of our laser sources as well as the cooling procedures, in order to realize lower temperatures and increased numbers of inverted atoms. Hence, we were obliged to execute an extended technical refinement program, which is discussed below in detail. This has led to substantial technical improvements, however, at the expense of a substantial time delay. This delay together with the shortly after the project start arising Covid pandemic made it impossible to achieve the expected results during the project duration. It was not until the end of 2024 that, based on the aforementioned extensive technical modifications, it finally became possible to realize quasi-continuous superradiant laser operation. It was possible to achieve emission over periods of up to 20 ms with a bandwidth of 180 Hz, significantly below the natural linewidth of the atomic 1S0 → 3P1 - intercombination line of 370 Hz.
Publications
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Towards a continuous wave superradiant calcium laser 18.07.2022, Toronto, Kanada The 27th International Conference on Atomic Physics
David Nak
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Towards a continuous wave superradiant Calcium Laser 09.03.2023, Hannover, Deutschland DPG spring conference Hannover SAMOP
David Nak
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Progress towards a continuous wave superradiant Calcium Laser 14.03.2024, Freiburg im Breisgau, Deutschland DPG spring conference Freiburg SAMOP
David Nak
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Progress towards a continuous wave superradiant Calcium Laser 15.05.2024, Hamburg, Deutschland Cavity control of quantum materials
David Nak
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Progress towards a continuous wave superradiant Calcium Laser 16.07.2024, London, Vereinigtes Königreich The 28th International Conference on Atomic Physics
David Nak
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Towards a continuous wave superradiant Calcium Laser 17.03.2024, Online DPG spring conference, Erlangen SAMOP
David Nak
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Towards a quasi-continuous superradiant calcium laser 17.10.2024, Boulder, Colorado, USA JILA Science Seminar, eingeladener Gastvortrag
David Nak
