Their apparatus uses many microplasma generators in a large array, which emit light through a clear, transparent window. Unlike fluorescent lamps, which require the electrodes to be far apart in a cylindrical cavity and vacuum conditions, microplasma light sources can be put into many different shapes and configurations, and generate heat. This is opposed to the more commonly used fluorescent lamps which require a noble gas atmosphere (usually argon), where eximer formation and resulting radiative decomposition strikes a phosphor coating to create light.[7] Excimer light sources are also being produced and researched.