Abstract We have studied, for the first time experimentally, the efficiency and spectral responsivity of an autocorrelation technique that is based on second harmonic generation from metal surfaces. High-quality autocorrelation traces are obtained with pulse energies as small as only 64 pJ (intensity ∼6.5 MW/cm 2 ), resulting in an efficiency that is comparable with existing nonlinear-crystal-based autocorrelation techniques. Our scheme, however, has a number of significant advantages over most existing autocorrelation techniques because it is dispersion-free and provides automatic phase matching over an extremely wide spectral range. This technique has potential for temporally characterizing any light source with a super-broad spectrum, a task that cannot be accomplished with existing techniques.