We have observed magnetic Feshbach resonances in the ultracold ⁴¹K+Cs mixture! (01/10/2024)
Our group is the first one in the world to have observed magnetic Feshbach resonances in this ultracold mixture. Theoretical predictions turned out to be extremely misleading and our observations will now force theorists to rethink what they know about molecular potentials of KCs molecules. Look out for the preprint, it should arrive soon!

The first in the world ultracold mixture of ³⁹K and ⁴⁰K has been published in Optics Express! (30/12/2024)
We present a dual isotope magneto-optical trap (MOT), simultaneous sub-Doppler laser cooling, and magnetic trapping of a spin-polarized ³⁹K-⁴⁰K Bose-Fermi mixture realized in a single-chamber setup with an unenriched potassium dispenser as the source of atoms. We are able to magnetically confine more than 2.2×10⁵ fermions (F=9/2, m_f=9/2) and 1.4×10⁷ bosons (F=2, m_f=2) with a lifetime exceeding 1.2 s. For this work, we have developed a versatile laser tailored for sub-Doppler cooling of all naturally occurring potassium isotopes and their mixtures. This laser system incorporates innovative features, such as the capability to select an isotope by activating or deactivating specific acousto-optic modulators that control the light seeding tapered amplifiers. Switching between isotopes takes ≈1μs without any mechanical adjustment of the components. Opt. Express 32, 48463-48478 (2024)

Sub-Doppler cooling of natural abundance ⁴⁰K has been published in Journal of Physics B: Atomic, Molecular and Optical Physics (9/02/2024)
We report on reaching sub-Doppler temperatures of ⁴⁰K in a single-chamber setup using a dispenser-based potassium source with natural (0.012% of ⁴⁰K) isotopic composition. With gray molasses cooling on the D₁-line following a standard D₂-line magneto-optical trap, we obtain 300 000 atoms at ≈10μK. J. Phys. B: At. Mol. Opt. Phys. 57 03530

Open-source magnetometer paper is out! (23/09/2023)
We demonstrate a fully automated open-source magnetometer designed primarily for characterization of magnetic fields produced by coils, permanent magnets or by parasitic sources. It is based on an Arduino Mega microcontroller and a three-axis Hall sensor. For all practical purposes, the sensor displacement during data acquisition is virtually unlimited, which can be particularly useful for characterizing large or extended coils like Helmholtz cages or Zeeman slowers. All components needed for the construction are cheap and widely available off-the-shelf elements or are 3D-printed. The operation of the magnetometer is controlled via a graphical user interface (GUI), which manages all essential functionalities, like data acquisition and plotting. Appl. Sci. 2023, 13(19), 10620

Sub-Doppler cooling of natural abundance ⁴⁰K pre-print is out! (31/07/2023)
We report on reaching sub-Doppler temperatures of ⁴⁰K in a single-chamber setup using a dispenser-based potassium source with natural (0.012% of ⁴⁰K) isotopic composition. With gray molasses cooling on the D₁-line following a standard D₂-line magneto-optical trap, we obtain 300 000 atoms at ≈10μK. arXiv:2307.16469

v=0 and v=1 in the 0^–_g found!
We use photoassociation (PA) of spin polarized (F=3, m_f=3) ultracold cesium atoms confined in a 1D optical lattice to confirm the existence of two lowest lying vibrational levels in the 0^–_g purely long-range state of Cs₂. The observation of these two levels confirms the theoretical predictions of Bouloufa et al. [1] postulating that the numbering of vibrational levels of this state needs to be shifted by two in order to agree theory with experimental data. We also provide unambiguous evidence that the work of Zhang et al. [2], which claimed priority of observing these new levels, in fact observed levels belonging to the 0⁺_u molecular potential.

Our first paper is out! (8/11/2021)
We present a new design of a bidirectional, analog current source we use for control of a uniform magnetic field with our compensation coils. We exploit the magnetic field dependence of gray molasses cooling to compensate stray magnetic fields in our UHV chamber. Our method is very intuitive and fast. We use it to achieve record breaking sub-Doppler temperature below 8 μK after gray molasses cooling of ³⁹K. Appl. Sci. 2021, 11(21), 10474

Crossed optical dipole trap filled with cesium. It’s first that cold cesium in the country! (07/30/2020)
After many, many troubles with the fiber amplifier we used a single mode fiber to spatially filter out higher order modes to improve the beam quality. The horizontal beams cross inside the vacuum chamber creating trapping potential for atoms.

The first formation of ultracold cesium molecules in our lab.(07/02/2020, 6 p.m.)
We have observed atom loss resulting from the formation of excited state cesium molecules. At this stage it is done in a magneto-optical trap and we are working towards photoassociation spectroscopy of potassium and cesium molecules.

The only ultracold alkali fermions in the country!! We have just trapped the third stable potassium isotope, ⁴⁰K. (3/11/2020, 11 a.m.)
We are now able to trap all stable potassium isotopes, ³⁹K and ⁴¹K (bosons) and ⁴⁰K (fermion) in a magneto-optical trap. The fermionic cloud contains only several tens of thousands atoms due to low natural abundancy of this isotope. These small numbers make it hard to do experiments with fermions, but the demonstration of trapping of ⁴⁰K is an important test of the capabilities of our experimental setup. We are now confident, that with a ³⁹K-⁴⁰K machine currently under construction we will be able to do some serious physics with degenerate fermi gases.

First dual species magneto-optical trap of ³⁹K+Cs and ⁴¹K +Cs (globally!!) (2/12/2019, 4 p.m.)
After a series of modifications and improvements, our setup is finally able to trap an ultracold atomic mixture of two bosonic isotopes of potassium and cesium. As of now we are the only research group in the world that demonstrated such a capability. In the picture above, potassium clouds are offset with respect to the cesium cloud on purpose, to highlight the presence of two species. Both species have different magnetic moments, therefore a uniform magnetic field applied with compensation coils effectively creates two different magneto-optical potentials.

First potassium (₄₁K) magneto-optical trap in Poland! (18/10/2019, 4 p.m.)
At 4 p.m. on 18/10/2019 we have observed our first ultracold cloud of ⁴¹K atoms. Now, we are in a position to mix ⁴¹K with cesium and look for interspecies Feshbach resonances in this mixture, for the first time ever.

First potassium (³⁹K) magneto-optical trap in Poland! (27/08/2019, 7 p.m.)
At 7 p.m. on 27/08/2019 we have observed our first ultracold cloud of ³⁹K atoms. With this achievement, our experimental setup is officially ready for experiments with ultracold mixtures of cesium and potassium. Stay tuned, we will be posting updates on our progress regularly.

First cesium magneto-optical trap in Poland! (22/08/2019, 6 p.m.)
At 6 p.m on 22/08/2019 we have observed our first ultracold cloud of cesium atoms. This is a great success of the master students involved in the project and is the first step towards Bose-Einstein condensation of cesium atoms.

Our ultracold story has just begun…