Balakshy Vladimir, Kupreychik Maxim, Mantsevich Sergey, Molchanov Vladimir
Faculty of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia.
Scientific and Technological Centre of Unique Instrumentation of the Russian Academy of Sciences,117342 Moscow, Russia.
Materials (Basel). 2021 Jan 18;14(2):451. doi: 10.3390/ma14020451.
This paper presents the results of theoretical and experimental studies of anisotropic acousto-optic interaction in a spatially periodical acoustic field created by a phased-array transducer with antiphase excitation of adjacent sections. In this case, contrary to the nonsectioned transducer, light diffraction is absent when the optical beam falls on the phased-array cell at the Bragg angle. However, the diffraction takes place at some other angles (called "optimal" here), which are situated on the opposite sides to the Bragg angle. Our calculations show that the diffraction efficiency can reach 100% at these optimal angles in spite of a noticeable acousto-optic phase mismatch. This kind of acousto-optic interaction possesses a number of interesting regularities which can be useful for designing acousto-optic devices of a new type. Our experiments were performed with a paratellurite (TeO) cell in which a shear acoustic mode was excited at a 9∘ angle to the crystal plane (001). The piezoelectric transducer had to nine antiphase sections. The efficiency of electric to acoustic power conversion was 99% at the maximum frequency response, and the ultrasound excitation band extended from 70 to 160 MHz. The experiments have confirmed basic results of the theoretical analysis.
本文介绍了由相控阵换能器在相邻部分反相激励下产生的空间周期性声场中各向异性声光相互作用的理论和实验研究结果。在这种情况下，与非分段换能器相反，当光束以布拉格角落在相控阵单元上时，不存在光衍射。然而，衍射会在一些其他角度（这里称为“最佳”角度）发生，这些角度位于与布拉格角相反的两侧。我们的计算表明，尽管存在明显的声光相位失配，但在这些最佳角度下衍射效率仍可达到100%。这种声光相互作用具有许多有趣的规律，可用于设计新型声光器件。我们的实验是在一个碲酸钡（TeO）单元上进行的，其中在与晶体平面（001）成9°角的方向上激发了剪切声模。压电换能器有九个反相部分。在最大频率响应下，电声功率转换效率为99%，超声激发带宽从70 MHz扩展到160 MHz。实验证实了理论分析的基本结果。
