An absolute gravimetric measurement device by atomic interferometry for geophysical applications particularly for monitoring hydrocarbon reservoirs

A device comprising a laser system (13) for generating a plurality of laser bands, such laser bands being each conformant at a frequency equal to an energetic transition between a hyperfine level (Fl, F2) of a fundamental state (52Si/2) and a hyperfine level (F'2,F'3) of an excited state (52P3/2) of said plurality of atoms, wherein the laser system (13) comprises a first laser source (23) stabilized in frequency which emits a first band (30), a second laser source (24), connected in phase with the first laser source (23), which emits a repumping band (37), said first (23) and second (24) laser source being coupled with means for generating secondary bands (29) capable of generating a detection band (31), a band for producing the three- dimensional magneto-optical trap (32), a thrust band (33) and a reference band (36), said laser system also comprising means for generating Raman bands (39) capable of producing two exiting superimposed Raman interferometric bands (41) starting from the reference band (36), the means for generating Raman bands (39) being associated with means for generating cooling bands (40) additionally coupled with the repumping band (37) and capable of generating three bands (53) for obtaining a magneto-optical trap.