Acoustic Michelson interferometer based on a phononic crystal

A practical and highly sensitive acoustic Michelson interferometer with a small form factor is introduced. It involves two different types of phononic crystals composed steel rods in water acting as medium for self-collimated waves mirrors the reference sample beams, well beam splitter formed by modified scatterers arranged diagonally. Finite-element method simulations are employed to demonstrate its operation around 200 kHz. Equifrequency contour analysis reveals self-collimation ultrasonic between 190 210 Introduction mirror not detrimental where outgoing from arms interfere such that output intensity varies cosine squared manner. Consequently, maximum sensitivity achieved when movable displacement either zero or half crystal period. On intervals these ranges, micrometer-scale resolution achievable, drops 0.2% per micrometer. Thus, displacements smaller than percent wavelength easily resolvable. Nanoscale can be obtained scaled down design. Moreover, application liquid concentration sensing considering ethanol–water binary mixture demonstrated. increase weight fraction ethanol up 10% leads an drop high 2%. significantly higher sensitivities compared schemes based on resonance frequency shift attainable. The proposed approach adapted surface strain measurement biosensing.