High-precision measurement of refractive index in explosive-driven air blast waves for density and pressure determination

Air refractive index alteration is an important research technique used to examine blast density and pressure. However, precise time-course measurements of changes at a fixed point caused by air waves are challenging due the necessity for high precision noise immunity. This study proposes dual-probe, dual-frequency fiber-optic displacement interferometer that achieves nanometer-level accuracy can tolerate light intensity fluctuations transmission-fiber interference. The specially designed sensor enables measurement resulting from explosive-driven waves, further allowing obtaining pressure information.