The method of visualization of spatially inhomogeneous acousic fields from micro-objects on the basis of acousto-optic interaction in the system with double Fourier transform

Background and Objectives: The method of acousto-optic visualization based on a double Fourier transform is presented. In a hybrid acousto-optic processor, the double Fourier transform is realized in the process of converting an acoustic signal from an object by an acoustic lens formed by the conjugate spherical surfaces of two crystals, and the subsequent processing of light diffracted in a photoelastic medium by an optical collecting lens. The possibility of using of this method for displaying high-resolution acoustic fields from micro-objects with characteristic dimensions of tens of micrometers is considered. The dependence of the resolution of the visualization device on the parameters of the acoustic and optical systems, as well as the image registration system, is studied. Materials and Methods: An optical system for introducing a laser beam is presented, which simultaneously improves the resolution of the device and ensures the observation of acoustic fields in a wide angular spectrum. Formulas for theoretical estimation of the resolution of components of a acousto-optic processor are presented. It is shown that to obtain the same resolution of the acousto-optic processor in orthogonal directions of an acoustic object, it is necessary to implement an optical system with an angular resolution in the planes corresponding to these directions, equal to the ratio of the angular resolution of the acoustic lens to the anamorphization coefficient. Results: The experimental verification of the acousto-optic processor functionality is carried out. Theoretical and experimental estimations of the resolution of the device as a whole are given. Conclusion: The advantage of using the visualization method based on acoustooptic interaction in a double Fourier transform system for observing micro-objects with high resolution is proved.