A system of two detectors separated by a narrow gap provides information regarding the diameter and flux distribution of small focused light spots. Differential signal variations in response to gap position for three flux distributions are theoretically analyzed: constant intensity, linearly diminishing intensity, and Gaussian. A PbZrTiO3pyroelectric split detector was fabricated for analyzing spots as small as 6 &mgr; (half‐intensity diam). Data taken on a focused He&sngbnd;Ne laser spot (≈25 &mgr; half‐intensity diam) are compared with expectation curves. Suggestions for improving resolution and sensitivity are made.