8-12 July 2019
Cité des Congrès
Europe/Paris timezone

Generation of very high-order and high-purity Gaussian modes

Not scheduled
2h 30m
Auditorium 450 (Cité des Congrès)

Auditorium 450

Cité des Congrès

5, rue de Valmy, Nantes, France Site web : https://lacite-nantes.fr/


Walid Chaibi (CNRS)


While lasers used for high-precision experiments typically generate an output beam in the fundamental TEM$_{00}$ mode, higher-order Hermite-Gaussian (HG$_{l,m}$) or Laguerre-Gaussian (LG$_{p,q}$) modes can be beneficial for various applications. For instance, metrology experiments which use optical cavities or laser interferometers are fundamentally limited in their length sensing sensitivity by thermally-induced mirror surface motion. The effect of thermal noise can be mitigated by using a spatially broader intensity profile for the laser beam compared to the TEM$_{00}$ mode. It has been predicted that mitigation of thermal noise can be achieved by higher-order modes and that the mitigation efficiency increases with the total mode order N (N = l + n for HG$_{l,m}$ and N = 2q + p for LG$_{p,q}$).
We experimentally demonstrate the conversion of the TEM$_{00}$ laser mode at 1064nm to higher order HG modes of arbitrary order via a commercially available liquid crystal Spatial Light Modulator (SLM). We particularly studied the G$_{5,5}$/HG$_{10,10}$/HG$_{15,15}$ modes. A two-mirror plano-spherical cavity filter the higher-order modes spatially. We analyze the cleaned modes via a three-mirror diagnosis cavity and measure a mode purity of 96%/93%/78%. These modes are then converted into high-order LG modes which are also of particular interest in cold-atom physics.

Choix de session parallèle 1.4 Mesures de précision avec des peignes de fréquence optiques

Primary authors

Mr Stefan Ast Mrs Sibilla Di Pace Mr Jacques Millo Mr Mikhael Pichot Mrs Margherita Turconi Walid Chaibi (CNRS)

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