Device for measuring laser radiation by photoacoustic effect

A device (D) for measuring laser radiation via the photoacoustic effect, comprising:

• a cell (C) containing at least one gas (G) having an absorption line with a central wavelength λc,
• an electro-acoustic transducer (MP) which is a microphone comprising a diaphragm (DP) and a package (BE) that is impermeable to the one or more gases, the diaphragm being arranged within the cell and being suitable for generating an electrical signal (Si) representative of the photoacoustic signal in the cell, the cell (C) being formed by said package,
• means (UT) for processing the electrical signal generated by the electro-acoustic transducer, in which processing means an estimate of the concentration of the one or more gases is stored,
• at least one laser source (L) suitable for emitting, into the cell, laser radiation (LL) at a wavelength suitable for exciting at least one gas contained in the cell, said laser radiation having a wavelength that varies in an oscillatory manner about an average wavelength λmoy at a modulation frequency (f1) or an optical power that varies in an oscillatory manner about an average power at said modulation frequency (f1), such that an interaction between the laser radiation and at least one gas contained in the cell induces generation of a photoacoustic signal at a detection frequency of the electro-acoustic transducer,
• said cell being sealed by a membrane (MB) so as to be impermeable to the one or more gases contained in the cell and having an optical aperture transparent to the laser radiation,
• said cell having dimensions smaller than 3 millimeters (mm) by 4 mm by 1.2 mm,
• said processing means being suitable for determining the wavelength of the laser radiation from the photoacoustic signal.