HIGH-Q ULTRASONIC RESONATOR METHOD USING OPTICAL DIFFRACTION FOR LIQUIDS

A new ultrasonic resonator method for measuring the ultrasonic absorpt ion in liquids in the low-frequency range 0.1 similar to 2 MHz is prop osed. The method utilizes Raman-Nath light diffraction to detect a res onance spectrum of standing waves in a resonator. The resonator is com posed of a quartz transducer and a concave reflector with a very sligh t curvature, which successfully reduces the diffraction effect at low frequencies. The usefulness of this apparatus is demonstrated by measu ring the absorption in water and benzene.