METHOD OF DUAL-BEAM THERMAL LENS MEASUREMENT WITH BACK SIGNAL SYNCHRONIZATION Russian patent published in 2017 - IPC G01N21/17 

FIELD: measuring equipment.

SUBSTANCE: method includes, at least, two measuring cycles, each of which consists of a test object heating half-cycle with a laser beam and a cooling half-cycle with a closed or disabled laser beam. The formation of the thermal lens field and measurement of the probe laser beam signal are performed in the heating half-cycle, as it passes through the formed stationary thermal lens. The measurement of the probe laser signal beam is performed in the cooling half-cycle in the full absence of the thermal fields induced by the laser radiation. The total times of the heating and the cooling half-cycles do not coincide, and each half-cycle begins only after the test defined as the non-excess of the maximum relative standard deviation of the probe beam signal measurement convergence, that corresponds to the equilibrium thermal state attainment of the test object.

EFFECT: increasing the sensitivity and accuracy.

3 cl, 2 dwg, 1 tbl