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Q-FARM Seminar presents "Direct laser cooling of polyatomic molecules"

Event date: 
Wednesday, January 13, 2021 - 12:00 pm
Speaker: 
Debayan Mitra (Harvard University)
Abstract: 

Laser cooling and evaporative cooling are the workhorse techniques that have revolutionized the control of atomic systems. In recent years, direct laser cooling has been successfully adapted to several diatomic molecules and now we seek to broaden these successes by extending its use to polyatomic molecules. The complex vibrational and rotational structure of polyatomic molecules makes it challenging to photon cycle but generically gives rise to closely spaced opposite parity levels in low lying excited states. These parity doublets allow full polarization at low electric fields, a significant advantage for a range of applications such as precision measurement, quantum computation and quantum simulation. We have recently demonstrated a nearly closed cycling scheme leading to optical cooling and a one dimensional magneto-optical trap (MOT) of calcium monohydroxide (CaOH) molecules [1]. We have also demonstrated Sisyphus cooling on the symmetric top molecule (STM) calcium monomethoxide (CaOCH3) lowering a molecular beam temperature by an order of magnitude [2]. I will discuss these results and present the roadmap for the future of this technique.

 
[1] Baum, et. al., Phys. Rev. Lett. 124, 133201 (2020)

[2] Mitra, et. al., Science 369, 6509 (2020) 

Bio: 

Debayan is a postdoctoral fellow at Harvard University and a member of the MIT-Harvard Center for Ultracold Atoms. He finished his bachelors in physics at Presidency College, India and went to France to do a masters at Ecole Polytechnique. Debayan did his PhD at Princeton in the group of Waseem Bakr, where he helped build a quantum gas microscope for fermionic lithium atoms. With that tool, he investigated the Fermi-Hubbard model in detail. For his postdoc in the group of John Doyle, he is working on directly laser cooling and trapping polyatomic molecules like CaOH and CaOCH3. These (ultra)cold molecules will be ideally suited for quantum computation and simulation applications in the future.