Phononic Crystal Composite Lens Imaging

Lens of phononic spherical surfaces have some difficult problems in spherical aberration and processing because of spherical surfaces properties so that flat lens image have become dream lens. Phononic crystal negative refracting offers an effective way to panel image. This paper mainly uses multiple-scattering theory (MST) to carry a research on the dimensions (2D)(iron air)triangle alignment voice sub-crystal. Firstly, made a discussion among Single flat、double flat and multi-panel of phononic crystal panel; Secondly, analyzed the influence of panel thickness to equivalent negative refractive index and image; Thirdly, conducted a preliminary exploration of band-gap design of phononic crystal from the experimental point of view. The result can be as follows:As for the dimensions (2D)(iron air)triangle alignment voice sub-crystal, only when incident wave shoot to a voice sub-crystal flat panel at certain frequency scope and certain angle of incidence, will the phenomenon of negative refract happen.The rules of phononic crystal flat imaging can be described by borrowing equivalent negative refractive index and the traditional refractive rules.As for such combination panel as double flat and multi-panel, its processing is similar to case of conventional geometric optical system of spherical surfaces, so the concepts, such as real/virtual object and image etc, can also be employed utility.The thickness of phononic crystal panel has some influence in equivalent negative refractive index. Through analysis, a conclusion can be made that the absolute value of equivalent negative refractive index will decrease with the increase of thickness. But the effect is small, it can be ignored.From the imaging point of view,the range of image will increase with the thickness of panel increasing.As for Multi-flat imaging system,keeping system object distance and total thickness of the panel unchanged,the distance between two panels has no influence in distance between the system image,which can greatly facilitate the use of flat lenses.Finally, build a test system of one-dimensional phononic crystals. The debugging over phononic characteristics of the measuring system proved that using upper and lower chamber system can finish the test over sound absorption rate and voice band of the materials.