presence of predetermined atoms in the ambient air the atomizer 104 has a combustion flame 110 which provides the desired atomization thus the atomizer 104 operates at the ambient pressure and detection of the atoms in the ambient air is made at the ambient pressure a laser 112 powered by a power supply 114 which may be similar to the laser 72 and power supply 76 described above generates a photon beam 116 having an intensity corresponding to a saturation intensity for the particular atoms that are to be detected and contains photons at a wave length corresponding to the resonant transition of the atoms to be detected the photon beam 116 is also preferably substantially free of photons at a wave length corresponding to the resonant fluorescent wave length that is to be detected a power meter 118 which may be similar to the power meter 84 described above receives the photon beam 116 after it has traversed the area containing the flame 110 wherein the atomization is provided in the embodiment 102 the gaseous products of combustion provide the buffer gas in the regions containing the atoms to be detected a detector 120 is provided and may be similar to the detector 86.