无衍射贝塞尔二次谐波传播和谐波成像的研究

investigated. This includes the analysis of the second-harmonic generation in the.high-order Bessel beam and the X wave beam, and the higher harmonic generation in.the zeroth and high order Bessel beams. The nonlinear propagation of Bessel second.harmonic beam in lossy media and Bessel ultrasonic harmonic imaging are also.analyzed in the present Project. In addition, we present an alternative approach to.calculate the second-order field of finite-amplitude sound beams. The nonlinear.propagation features of Bessel beams are obtained from the KZK equation in.nonlinear acoustics, and the primary experiments verity these results. This study is as.the fundamental of the further analysis of nonlinear features of the other.nondiffracting beams and is helpful for better understanding the physical properties of.these beams. The study has potential applications in the development of ultrasonic.imaging with good quantity, specially in medical imaging, and the harmonic imaging.of ultrasound

无衍射波束目前成为声学和光学等领域中研究热点。无衍射声场在非线性媒质中传播具有新的物理现象。从理论和实验上研究贝塞尔二次谐波声束的超高分辨率性质，和谐波成像机理，包括各种无衍射声场的实现方法。探索其在超声成像、材料非线性参数测量等方面的潜在应用。建立一套无衍射非线性成像系统。