A method for the molecular detection based on the determination, or measurement, respectively, of the relaxation behavior, in particular of the relaxation time, of nanoparticles dispersed, or suspended in a fluid medium, to which, or on the surface of which, the target molecules, target molecule sequences, target molecule particles, or target organisms are bound specifically or non-specifically, - wherein said particles charged in this manner may be aligned, at least predominantly, in the dispersion or suspension in a spatial direction under the influence of an external stimulus, preferably a directional field, in particular an electric and/or magnetic field, and - wherein said particles are transferred in the dispersion or suspension, either based from an initially stochastic, statically inordinate, non-directional state, to a finally at least predominantly uniformly directional state, or vice versa, - and the behavior, or the properties of the dispersion or suspension is detected in each of the two states, and/or between said states, and in particular the time between the two states is detected, and a conclusion is drawn from the relaxation behavior determined in this manner as to the concentration, and/or size, and/or property of the target molecules, target molecule sequences, target molecule particles, or target organisms bound to the micro or nanoparticles, - wherein, for determining the relaxation behavior, a suspension or dispersion is utilized, the nanoparticles of which - in addition to its capability of geometric location alignment - have an optical anisotropy, - wherein either a) particularly linear, polarized, or b) non-polarized light is radiated into said suspension or dispersion, and - wherein the light exiting as scattered light - either directly absorbed in the irradiation direction, or by means of absorption, or at an angle to the same, as such is subjected to an optometric analysis, directly, or after passing through a polarization filter downstream of the dispersion or suspension being traversed by the light, characterized in that the nanoparticles present in the dispersion or suspension, capable of being aligned by the external stimulus, in particular by means of the external field, are comprised, or contain precious metals, in which anisotropic Plasmon resonances having characteristic scattering and/or extinguishing spectra, or changes in the same, are excited by incident light. - wherein said particles charged in this manner may be aligned, at least predominantly, in the dispersion or suspension in a spatial direction under the influence of an external stimulus, preferably a directional field, in particular an electric and/or magnetic field, and - wherein said particles are transferred in the dispersion or suspension, either based from an initially stochastic, statically inordinate, non-directional state, to a finally at least predominantly uniformly directional state, or vice versa, - and the behavior, or the properties of the dispersion or suspension is detected in each of the two states, and/or between said states, and in particular the time between the two states is detected, and a conclusion is drawn from the relaxation behavior determined in this manner as to the concentration, and/or size, and/or property of the target molecules, target molecule sequences, target molecule particles, or target organisms bound to the micro or nanoparticles, - wherein, for determining the relaxation behavior, a suspension or dispersion is utilized, the nanoparticles of which - in addition to its capability of geometric location alignment - have an optical anisotropy, - wherein either a) particularly linear, polarized, or b) non-polarized light is radiated into said suspension or dispersion, and a) particularly linear, polarized, or b) non-polarized light is radiated into said suspension or dispersion, and - wherein the light exiting as scattered light - either directly absorbed in the irradiation direction, or by means of absorption, or at an angle to the same, as such is subjected to an optometric analysis, directly, or after passing through a polarization filter downstream of the dispersion or suspension being traversed by the light,