Mathis Roussel (03/2024-08/2024): Mathis worked on the experimental setup to reproduce and go beyond an experiment demonstrated by the group of Prof. Jaewook Ahn (KAIST, Korea) on accelerating, throwing and recapturing atoms with moving optical tweezers. He succeeded! and by throwing atoms, we can now bring them at much closer distance to each other’s than previously with static tweezers. Thanks Mathis and now enjoy your master at ETH Zurich.

Axel-Ugo Leriche (03/2024-08/2024): Axel worked on the theoretical aspect of throwing and catching atoms with optical tweezers, together with Mathis (see above post). He generated helpful simulations guiding us in the good choice of parameters, as well as illustrative animations of moving tweezers (and flying atoms) that everyone in the group (and visitors) enjoyed much. Congrats Axel-Ugo and best wishes for your master 2 in Paris.

Omar Kecir (04/2024-08/2024): While our group has been extensively using Phase-Only Spatial Light Modulators for creating holographic optical patterns, Omar was given the job to do this with a Digital Micro-Mirror device. It consists of millions of tiny mirrors that can be flipped in one direction or the other. Omar learnt how to use them in an holographic configuration by displaying a grating of on/off mirrors that diffracts an incoming laser beam. The first order diffracted beam is imprinted by the local phase of the grating, allowing to perform holography. Omar demonstrated wavefront correction (which is seriously perturbed by the DMD surface which is far from flat) and learnt a few new tricks and bugs on the DMD. Good job Omar, and see you in one month to start your PhD on the Quantum Computer project.

Isaline Duperon (05/2024-08/2024): Isaline continued the project of Bee on characterizing SLM (Spatial Light Modulators) based on liquid crystals. In particular, she tackled the question of the noise imprinted by the SLM on the laser beam, an important point when considering that the laser beam will be used for very precise manipulation of neutral atoms (trapping, excitation, …). She developed an optical test-bench for measuring the phase noise imprinted by the fluctuating liquid crystals and measured it for the first time in our laboratory (and we didn’t find other measurement in the open scientific literature!). She also compared the performance of two SLMs from different manufacturers. Finally, she pushed her project further and measured the intensity noise of a holographic tweezers array generated with the SLM. Thanks Isaline for your effort, the knowledge gained in this project helps us to understand more the possible errors caused by SLM. Have fun for your Master in Stockholm.   

“Bee” Phatwarach Siriworakoonchai (02/2024-06/2024): This project focuses on the setup, optimization, and testing of high-speed Spatial Light Modulator (SLM) systems, achieving operation at 1 kHz. Bee  is developing software that aims to enable parallel atom manipulation and versatile single-atom addressing patterns with SLM. The advancement promises significant enhancements in the flexibility and efficiency of optical tweezer arrays, marking a critical step forward in quantum manipulation techniques.

Karthikeyan Ganesan (07/2023-05/2024): Karthikeyan’s project revolved around trying Rydberg excitation of Rubidium atoms using a homebuilt 780 nm cw laser as well as a commercial 480 nm laser. Thanks to a collaboration with the group of Prof. Christian Gross (Tubingen, Germany), we learnt about their design of IF-ECDL laser and reproduced it successfully in our laboratory. After constructing and testing the laser, Karthikeyan then stabilized its frequency with a PDH lock on a highly-stable Fabry-Perot cavity. He then shone the 780 and 480 nm lasers to the atoms to test Rydberg excitation and could get a signal in the last week of his project: nice job Karthikeyan !

Arnab Maity (07/2023-05/2024): Arnab focused his effort on characterizing and using a chirped Bragg grating (CBG), a highly dispersive optical component, for spectral shaping of our picosecond pulses. For our ultrafast Rydberg experiments, we require pulses with a duration of 10 – 100 picoseconds to perform excitation of a valence electron from its ground state to a giant Rydberg orbital. Our group is interested in using CBGs to imprint a large chirp on our pulses. His work was first to precisely characterize the CBG chirp, for which he developed 2 test benches resulting in a measurement precision 10 times better than the results of the CBG manufacturer! Followingly, he used the CBG and the chirped laser pulse to perform an advanced type of coherent excitation called Rapid Adiabatic Passage.  His efforts resulted in a good step forward for our group in the ultrafast manipulation of Rydberg states, and was later continued by Sapna. Thanks Arnab and best of luck for your PhD in France !

“Beam” Kittisak Ketaiam (01/2024-05/2024): Beam’s internship project was on optimizing the efficiency of Acousto-Optic Deflectors (AODs) for the parallel rearrangement of atoms within optical tweezers. By enhancing the AOD’s bandwidth and correcting wavefront aberrations, his work intends to improve the performance of moving tweezers, an important tool for cold-atom experiments.

Eduard Braun (02/2024-05/2024): Eduard worked on how a microwave drive could tune the interaction between Rydberg atoms. On one side, he developed the microwave hardware allowing polarization control across frequencies ranging from 24 to 60GHz. On the other side, he created a numerical model to explore how to choose the microwave parameters to precisely tune he Rydberg interaction, with potential applications of high fidelity two-qubit gates in neutral atom quantum computing.

Oscar Guillemant (05/2023-08/2023). Oscar joined the team during his summer holidays to work with Tom, his friend from childhoold ! Together, they produced multiple phase noise eaters. Thanks for your contribution, Oscar And enjoy working with NASA next!

Tom Denecker (04/2022-08/2022). After much patience for the Japanese border to re-open following the global health crisis, Tom could finally join the group for an internship. Following on a side project of Sylvain on measuring and correcting the fast phase noise of lasers, Tom took the project to the next step. While the initial setup was based on free-space optics, Tom upgraded it to a fiberized system and could successfully reproduce and improve the experiment. His project was continued by … himself … see Part II.

Takuya Matsubara (02/2022-03/2022): Matsubara-kun took a short break from his PhD studies in the field of atto-second science at Tokyo University and RIKEN, and briefly joined our group to work on much slower, nanosecond-scale, laser pulses (for us, they are still very fast though!). He made the first prototype for generating nanosecond-scale pulses at 780 nm using an electro-optic Pockel cell and obtained our first signal of Rabi oscillation between the electronic ground state (5S) and the first excited orbital (5P) of Rubidium atoms. This research project, started with Matsubara-kun is very active, with two follow-up student projects (see Part II and Part III) and even now one of the topics of the PhD of Robin Kocik. After completing his PhD, Matsubara-kun joined the group as a Research Assistant Professor, and now supervising some student projects!