METHOD OF OBTAINING TOPOGRAPHIC INTERFERENCE PATTERNS OF PHASE OBJECT Russian patent published in 2013 - IPC G02B27/50 G01B9/25 G01N21/958 

FIELD: physics.

SUBSTANCE: invention can be used in measuring small path differences (less than 0.1λ) of weak optical nonuniformities in transparent media, e.g., when flowing around bodies in low-density streams, spraying fuel from sprayers into an evacuated space, studying mixing processes, fuel ignition and combustion and detecting diffusion boundary layers. The method involves successively recording, on a recording medium, a reference beam and an object beam passing through the phase object. Before recording, the object beam is decomposed by a diffraction element into zero- and higher-order diffracted beams and the zero-order beam, passing through the phase object in both the forward and reverse path of diffracted light beams in the diffraction element, is used. N-order beams formed in the reverse beam path through the diffraction element are simultaneously returned to the plane of the diffraction element. In order to record the object and reference beams, the recording medium is placed in one of the N interfaced reverse N-order beams of the opposite sign of the reverse beam path. Measurement sensitivity coefficients are determined using the formula S=(N+1)·2, where N - (0, +1; +2; +3, +4…) is the diffraction order.

EFFECT: high measurement sensitivity coefficient.

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