OPTICAL AMPLITUDE EVALUATION OF SQUARE-WAVE PRESSURE

摘要

We have developed a system for the amplitude measurement of periodic square-wave pressure by measuring the change in refractive index of air. Using a differential interferometer and a pressure cell whose capacity was less than 5 cm~3, the change in the optical path difference between the reference and measurement paths was measured when square-wave pressure was applied in the cell. A rotating valve was used to vary the pressure in the cell. For the measurement in the amplitude range from 10 kPa to 100 kPa as gauge pressure, the pressure amplitude and the optical path difference were simultaneously measured as time series. In this study, the transient change in temperature of the medium due to the rapid change in pressure and the results of the optical amplitude measurement were examined.