17-22 July 2022
Royal Conservatory of Music, Toronto
America/Toronto timezone

Development of a Deep-ultraviolet Chirped Pulse Laser for Doppler Cooling of Positronium

18 Jul 2022, 17:00
1h 30m
Hart House (Hart House)

Hart House

Hart House

7 Hart House Cir, Toronto, ON M5S 3H3
Poster presentation Precision measurement and tests of fundamental physics Poster session

Description

Positronium (Ps), a bound state of an electron and a positron, is a purely leptonic and anti-particle system. Preparing a cold gas of Ps leads to precision spectroscopy and a realization of Bose-Einstein condensation of exotic atoms. Owing to the nature of the particle-antiparticle pair, Ps has a finite lifetime of 142 ns. Therefore, developing a rapid cooling method is the key to cool Ps effectively.
Laser cooling using the 1S-2P transition is one of the most promising methods for Ps cooling. With laser cooling, Ps atoms at room temperature could ideally be cooled to the photon recoil limit of 0.6 K within one microsecond. The temperature is well below 150 K, achieved by a conventional cooling method via momentum exchange processes with a cold Ps converter[1].
It is well known that laser cooling using continuous-wave lasers can reduce the temperature of a gas of atoms to submillikelvin temperatures[2]. However, because of the finite lifetime and the small mass of Ps, a cooling laser for Ps should be a unique pulsed laser that has a broadband spectrum, a frequency chirp, and a long pulse duration of several hundred nanoseconds[3]. We designed and developed a prototypical cooling laser (Figure 1) that satisfies these requirements. We also numerically simulated its oscillation dynamics and successfully reproduced the measured temporal and spectral structures of the laser[4].

Schematic of the prototypical cooling laser system.

[1] S. Mariazzi, P. Bettotti, and R. S. Brusa, Physical Review Letters 104, 243401 (2010).
[2] W. D. Phillips, Reviews of Mordern Physics 70, 721 (1998).
[3] K. Shu, X. Fan, T. Yamazaki, T. Namba, S. Asai, K. Yoshioka, and M. Kuwata-Gonokami, Journal of Physics B: Atomic, Molecular and Optical Physics 49, 104001 (2016).
[4] K. Yamada, Y. Tajima, T. Murayoshi, X. Fan, A. Ishida, T. Namba, S. Asai, M. Kuwata- Gonokami, E. Chae, K. Shu, and K. Yoshioka, Physical Review Applied 16, 014009 (2021).

Presenter name Tajima Yohei
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Primary authors

Yohei Tajima (Department of Applied Physics, School of Engineering, The University of Tokyo) Kyohei Yamada (Department of Physics, School of Science, The University of Tokyo) Takuto Kobayashi (Department of Applied Physics, School of Engineering, The University of Tokyo) Akira Ishida (Department of Physics, School of Science, The University of Tokyo) Toshio Namba (International Center for Elementary Particle Physics, The University of Tokyo) Shoji Asai (Department of Physics, School of Science, The University of Tokyo) Eunmi Chae (Department of Physics, College of Science, Korea University) Kenji Shu (Department of Applied Physics, School of Engineering, The University of Tokyo, Photon Science Center, School of Engineering,The University of Tokyo) Kosuke Yoshioka (Department of Applied Physics, School of Engineering, The University of Tokyo, Photon Science Center, School of Engineering,The University of Tokyo)

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