Disclosed is an acoustic resonance spectrometry system for analysing a sample, which includes an optical pump-probe device adapted to generate a pump beam and a probe beam, the pump beam being consisted of a series of ultra-short pump light pulses having a repetition frequency in the spectral domain of the gigahertz, the pump beam being directed towards an optoacoustic transducer to generate a periodic grating of coherent acoustic phonons in the sample, the probe beam being directed towards the sample to form a scattering beam of the probe beam on the grating of phonons, a frequency variation device being adapted to vary the repetition frequency of the pump beam in a spectral range and a photo-detection system configured to measure a scattering signal as a function of the repetition frequency in the spectral range.