We report on the use of Doppler-free 2 + 1 resonance enhanced multi-photon ionization (REMPI) to probe H atoms resulting from HBr photolysis at 243 nm. The Doppler-free technique allows almost all,H atoms to be ionized at a single probe wavelength, regardless of their lab-frame velocities. This technique yields a significant enhancement in ionization efficiency of the product while leaving the background ionization essentially unaffected. We point out the utility of this technique for the ion imaging of reaction products. (C) 2003 Elsevier Science B.V. All rights reserved.