We demonstrate controllable poration within ≈1 μm regions of individual cells, mediated by a near-IR laser interacting with thin-layer amorphous silicon substrates. This technique will allow new experiments in single-cell biology, particularly in neuroscience. As our understanding of the fundamental mechanistic processes underpinning biology expands, so does the need for high-precision tools to allow the dissection of the heterogeneity and stochastic processes that dominate at the single- and sub-cellular level. Here, we demonstrate a highly controllable and reproducible optical technique for inducing poration within specific regions of a target cell's plasma membrane, permitting localized delivery of payloads, depolarization and lysis experiments to be conducted in unprecedented detail. Experiments support a novel mechanism for the process, based upon a thermally-induced change triggered by the interactions of a near-IR laser with a biocompatible thin film substrate at powers substantially below that used in standard optoporation experiments.