A technique for measuring pressure of a material directs one or more laser beams at the material (e.g., a pressurized fluid) to create a distribution of electromagnetic field intensity which varies over an intensity range and induces dielectric breakdown in the material. An emission pattern of broadband light from the dielectric breakdown is detected, and a value of a characteristic of the emission pattern (e.g., location of a threshold intensity or of a peak intensity) is processed (e.g., by a computer or similar electronic processor) to generate a pressure measurement signal representing a pressure of the material. Processing typically employs a pre-established calibration function which associates a set of stored values of the characteristic with corresponding known pressures of the material, obtained for example by preceding similar measurements of the same material under conditions of known pressures.