Can Be Tuned Acoustic Resonator Acoustic Tunneling Effect Studies

In recent years, people use crystal structure of solid physics thoughts, for the inspiration of the electronic band theory in natural crystal, solid band theory is promoted to the mesoscopic scale and macro scale and used to examine classical wave radiation such as electromagnetic wave, sound waves and artificial crystal of the coupling effect. Hoping that through the research in classical wave composite material or structure of cycle spread, we will realize the control of the classical wave transmission, solve part of phononic crystal in the areas of physics foundation. In recent ten years, it is expected to have a breakthough in the region of Elastic wave. In1993by means of M.S.Kushwaha etc analogy the photonic crystals, they first put forward the concept of virtual phonons crystals (Phononic Crystals). At present, not only in the band gap mechanism, but also the band gap theory calculation theory have been made breakthrough progress, and it is took the significant progress in phnoonic crystal properties research, preparation technology and application processing. The research and application of photonic crystals have become wonderful power in optical physics research in the recent30years. Also the phononic crystal produces profound effect in solid state physics, materials science, it provide us new train of thought in the region of sound waves control and vibration control. It has its unique of development and application prospect.Analogying some physical properties of photonic crystals, it is also found that phnoonic crystal has the same properties. For instance, in the experimental of phononic crystal and the theoretical study, it is found some solid physics of quantum effects, such as:Bloch oscillations, Zener resonance tunneling, Wannier-Stark Ladder effects, etc.Based on the transfer-matrix method, theoretically we study the resonant tunneling effect of the acoustic wave in a tunable acoustic-phonon cavity made of two identical acoustic-phonon superlattices, which are similarly to Zener tunneling effect of the quantum mechanics. The acoustic wave tunneling kinetics process in the frequency gaps of the phonons superlattices is investigated by altering the length of the acoustic wave resonant-cavity. For the different frequency gaps, the tunneling characteristics are of difference, and the tunneling frequencies of the acoustic wave are periodic oscillations with the increase of the resonant-cavity. Meanwhile, based on resonant cavity we have studied the evolution of acoustic wave dynamic interchange between conduction band and stop band.In the resulting experiment, it is clear seen that energy coupling process of stop band boundary, which dynamically show transmission situation in the acoustic-phonon superlattices bandgap boundary. The theoretical and experimental results show that it is easy to come up the acoustic wave tunneling in the stop band.This paper is composed of the following four parts.The first part is transfer-matrix theoryIn this part, the basic concept of sound waves and main characteristics are introduced; In an ideal fluid medium, the physical sonic, basic equations are described; From different angle, based on the transfer matrix theory method, it is deducted that sound waves structure phononic crystal spread in the transfer matrix, eigen value equations, the reflectivity and transmission rate in a period, and a simple numerical simulation can be found.The second part is Zener resonant tunneling effect of the acoustic wave in phonon crysitalIn this part, borrowed the thought of Zener resonant tunneling effect in Quantum physics, we explained the Zener resonant tunneling effect of the acoustic wave in phonon crysital from a new perspective. According to the bandgap structure of phonon crysital,using two identical acoustic-phonon superlattices consist of the acoustic-phonon cavity. Based on the transfer-matrix method, we study the resonant tunneling effect of the acoustic wave in the tunable acoustic-phonon cavity we mentioned above. The acoustic wave tunneling kinetics process in the frequency gaps of the phonons superlattices is investigated by altering the length of the acoustic wave resonant-cavity as far as to adjust the tunneling frequency of acoustic wave. For the different frequency gaps, the tunneling characteristics are of difference, and the tunneling frequencies of the acoustic wave are periodic oscillations with the increase of the resonant-cavity, at the same time the oscillation cycle is smaller.The third part is acoustic wave dynamic evolvement in stopband edge of phonons superlatticesBased on the acoustic wave resonant cavity of varied length with two identical acoustic-phonon superlattices, we have researched the dynamic law of the junction between conduction band and stop band of superlattices, and the tunneling effect on the stopband edge. We can see in the resulting of experiment that energy coupling process in stop band boundary; theoretically we disclose the periodic evolution of the wave tunneling process in the stop band region with increasing the length of resonant cavity; The theoretical and experimental results both dynamically show the transmission situation in the acoustic-phonon superlattices bandgap boundary, it is easy to achieve the acoustic wave tunneling process in the stopband edge, the theory is in good accordance with the resulting of experiment.The fourth part is theory basic research of symmetrical acoustic phonon nano cavityThe local acoustic state of acoustic nano cavity is similar to the limited electronic energy levels and quantum potential trough of atom.By using this similarity and the concept in photonics,we described the way to control the new acoustic device(the resonator system is composited of basic module material) in the range of terahertz (nm wavelength) and studied how to modulate the sound waves spectrum and solve the question of its dynamic process.