Optical diagnostics are currently used for measurement of gas concentrations in environment or in biological systems. Most of them use absorption or phosphorescence spectroscopic techniques, or optical evanescent field-sensing techniques. We present a theoretical investigation of the modifications induced by phosphorescence quenching on the properties of nonlinear optical devices. Oxygen measurements are considered in this study. Oxygen is shown to strongly modify properties of bistable devices, and self-pulsing regime exhibited by laser with a saturable absorber. This prospective work demonstrates that nonlinear optical devices are promising candidates to realize very sensitive gas probes. (C) 2000 Elsevier Science S.A. All rights reserved.