A new imaging-based method for alignment of multiple laser beams

  Yair Yifrach  ,  Rami Rahimi  ,  Alexander Portnov  ,  Ilana Bar  
Department of Physics, Ben-Gurion University of the Negev, Beer-Sheva 8410501, ISRAEL

A new method for multiple laser beams alignment, useful in a wide range of spectroscopies, is proposed and demonstrated. The method, based on coupling of spatial map imaging (SMI) with velocity map imaging (VMI), aided beams visualization, through interrogation of the ionization signal of different species in a time-of-flight mass spectrometer. This attitude is very effective for alignment and for evaluating the spatial overlap of the laser beams with a molecular beam. This was demonstrated by monitoring the resonant two-photon ionization spectrum of 2-phenylethylamine (PEA) monomer and its water (PEA–H2O) cluster and the ionization-loss stimulated Raman spectrum of the cluster, via VMIs accumulation, as a function of the exciting laser wavelength. The former permitted immediate classification of the features in the spectrum, corresponding to the molecular ion or the cluster. The proposed methodology will be useful in other challenging multiple laser beam experiments for spectroscopic studies and is expected to improve extensively their outcome.