The present invention relates to a photoacoustic method that uses measurement light having a predetermined wavelength range to determine the properties of a heterogeneous sample, the sample having an average absorption length of 1-100 micrometer intervals for a predetermined wavelength range with μ, the method comprising: a) at the surface of a sample heterogeneous with at least one measuring light pulse having a predetermined pulse duration and a predetermined intensity. Examining the measurement region of the phosphorus region F； b) detecting at least one pressure transient in the measurement region, the pressure transient resulting from absorption of at least one measurement light pulse in a heterogeneous sample that generates a pressure wave propagating to the measurement region- ； c) at the beginning and end of the at least one measurement light pulse, calculating a value for the energy density absorbed by the sample for the duration of the pulse from a curve of at least one pressure transient； d) repeating steps a) to c) for different angles of incidence of the measured light with respect to the normal of the measurement region, where the energy density values determined in c) are each represented by the angle of incidence； e) modeling a heterogeneous sample as a stack of layers, wherein at least the layer's thickness and absorption coefficient are assigned to each layer, and the absorption coefficient of at least one layer is a custom parameter； f) performing a fitting procedure for the fit parameters of the stack of layers, where the division of the energy density value, expressed as the angle of incidence, into the contribution of individual layers to a change is made by changing the fit parameters until a predetermined consistency criterion is met. -； g) reading a fit parameter fitted as a value for at least the depth resolution absorption coefficient of the heterogeneous sample.본 발명은 불균질한 샘플의 특성을 결정하기 위해 미리 결정된 파장 범위를 갖는 측정 광을 사용하는 광 음향 방법에 관한 것으로서, 상기 샘
