Laser desorption source for molecular interferometry

Full text: Molecule interferometry requires sufficiently intense sources of cold, neutral and mass selected molecular beams. One possibility to produce a beam of molecules is laser desorption. In combination with a supersonically expanding gas beam this method is known to generate a large fraction of neutral particles. The cooling in the expanding gas beam has two major advantages: firstly it opens the possibility to desorb thermally instable molecules like most complex biomolecules. Secondly it reduces the divergence and velocity spread of the beam and therefore leads to an enhanced detection signal. We show that aminoacids like tryptophan and larger polypeptides like gramicidin can be neutrally desorbed. We monitor the desorbed beam using laser ionization and time of flight mass spectrometry. We discuss the possibility to apply this source for interferometry in combination with a standing light wave interferometer. (author)