Microelectronic photoacoustic detection device comprising: a substrate comprising cavities forming a Helmholtz differential acoustic resonator; acoustic detectors coupled to the chambers of the resonator; a light source; a waveguide comprising a first end coupled to the light source and a second end coupled to a first chamber; in which the second end comprises, at the interface with the first chamber, a width greater than that of the first end and that of the given wavelength, and/or in which the device comprises a diffraction grating arranged in the second end and capable of diffracting a first part of the beam towards a lower reflective layer arranged under the second end and a second part of the beam towards an upper reflective layer arranged at an upper wall of the first chamber.