Orateur
Description
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 |
|---|
