Mantsevich Sergey N, Yushkov Konstantin B
M.V. Lomonosov Moscow State University, 1 Leninskie Gory, Moscow 119991, Russia.
National University of Science and Technology MISIS, 4 Leninsky prospekt, Moscow 119049, Russia.
Ultrasonics. 2021 Apr;112:106335. doi: 10.1016/j.ultras.2020.106335. Epub 2020 Dec 30.
The method of quasicollinear acousto-optic tunable filters (AOTFs) piezoelectric transducer dimensions optimization is presented. The AOTFs with large interaction length apply the bulk acoustic wave (BAW) reflection from the input optical facet. Optimization is based on spectral approach to simulation of the BAW field in anisotropic media and Raman-Nath equations numerically solved for the inhomogeneous acoustic field. It was found that variation of the transducer dimensions can minimize RF power consumption of the AOTF. Comparison of the optimized transducer dimensions with those commonly used in quasicollinear paratellurite AOTFs showed that it is possible to improve the AOTF energy efficiency in about 2 times. It was shown that acoustic field simulation results obtained for one AOTF geometry can be applied to the other geometries but for equivalent frequency providing the same ultrasound beam ray spectrum width. It was also shown that when choosing the quasicollinear AOTF with reflection geometry, one should not rely only on the AO figure of merit value, since the energy efficiency of such AOTF type will be determined by the product of the AO figure of merit and the AOTF efficiency, which takes into account the change in the acoustic beam width in the reflection process. The results aim at improving the design of AOTFs for ultrashort laser pulse shaping.
介绍了准共线声光可调谐滤波器（AOTF）压电换能器尺寸优化的方法。具有大相互作用长度的AOTF利用输入光学面的体声波（BAW）反射。优化基于对各向异性介质中BAW场进行模拟的频谱方法以及对非均匀声场数值求解的拉曼-奈斯方程。结果发现，换能器尺寸的变化可使AOTF的射频功耗最小化。将优化后的换能器尺寸与准共线亚碲酸盐AOTF中常用的尺寸进行比较，结果表明，AOTF的能量效率可提高约2倍。结果表明，针对一种AOTF几何结构获得的声场模拟结果可应用于其他几何结构，但需满足等效频率且提供相同的超声束射线谱宽度。研究还表明，在选择具有反射几何结构的准共线AOTF时，不应仅依赖于声光品质因数的值，因为这种类型AOTF的能量效率将由声光品质因数与AOTF效率的乘积决定，其中AOTF效率考虑了反射过程中声束宽度的变化。这些结果旨在改进用于超短激光脉冲整形的AOTF的设计。
