INTERFERENCE METHOD FOR MEASURING PHASE SHIFT OF LIGHT WAVES Russian patent published in 1994 - IPC

FIELD: measurement technology. SUBSTANCE: method involves division of radiation of laser 1 incident onto acoustooptic modulator 2 by reference and measuring fluxes of different optical frequencies. Measuring flux is passed to measuring channel of interferometer 4. Reflected radiation is spatially aligned with reference flux radiation and sent to photodetector 6 whose output signal goes to input of measuring circuit and then to acoustooptical modulator 2. The reversal of polarity of measuring circuit conversion factor at extreme phase shift of light waves provides for elimination of time-limited discrete frequency processes in acoustooptic modulator 2 (frequency hopping) and to shape instead of them low-duration logical information pulses. Changing absolute value of measuring circuit conversion factor enables shaping of pulse-to-pulse spatial period of desired value. EFFECT: improved speed of response due to improved processing speed of measuring data; enlarged functional capabilities of laser heterodyne method of displacement measurements. 2 cl, 4 dwg