METHOD OF MEASURING PARTICLE SIZE OF SUSPENSIONS AND FOUR-WAVE MIXING LASER TO THIS END Russian patent published in 2011 - IPC G01N15/04 

FIELD: physics.

SUBSTANCE: proposed method comprises interference of light beams in light four-wave mixing. Two of said beams intersect in suspension to produce hyper sound lattice and turn to be reference beams. Third beam, a scanning one, reflects from said hyper sound lattice to generate fourth beam, a data beam, its amplitude varying with that of hyper sound wave generated by hyper sound lattice in suspension. Note here that third beam is polarised orthogonally to reference beams intensity modulated by hyper sound wave frequency. Variation of angle between reference beams causes variation in hyper sound wave length, which, when coincided with suspension particle size, brings about local minimum of hyper sound wave amplitude, hence, data wave amplitude minimum. Position of the latter on graph of data beam amplitude vs angle between reference beams and modulation frequency defines suspension particle size.

EFFECT: higher validity and accuracy.

2 cl, 1 dwg