M-Bonacci Zone Plates for Ultrasound Focusing

[EN] In this work, we present a thorough analysis on M-bonacci zone plates for ultrasound focusing applications. These planar lenses are capable of providing bifocal focusing profiles with equal intensity in both foci and become very appealing for a wide range of scenarios including medical and industrial applications. We show that in high-wavelength domains, such as acoustics or microwaves, the separation between both foci can be finely adjusted at the expense of slightly increasing the distortion of the focusing profile, and we introduce a design parameter to deal with this issue and simplify the design process of these lenses. Experimental measurements are in good agreement with numerical simulations and demonstrate the potential of M-bonacci lenses in ultrasound focusing applications. This work has been supported by Spanish MICINN RTI2018-100792-B-I00 project. S.P.-L. acknowledges financial support from Universitat Politecnica de Valencia grant program PAID-01-18. Pérez-López, S.; Fuster Escuder, JM.; Candelas Valiente, P. (2019). M-Bonacci Zone Plates for Ultrasound Focusing. Sensors. 19(19):1-13. https://doi.org/10.3390/s19194313 Chen, J., Xiao, J., Lisevych, D., Shakouri, A., & Fan, Z. (2018). Deep-subwavelength control of acoustic waves in an ultra-compact metasurface lens. Nature Communications, 9(1). doi:10.1038/s41467-018-07315-6 Molerón, M., Serra-Garcia, M., & Daraio, C. (2014). Acoustic Fresnel lenses with extraordinary transmission. Applied Physics Letters, 105(11), 114109. doi:10.1063/1.4896276 Li, Y., Yu, G., Liang, B., Zou, X., Li, G., Cheng, S., & Cheng, J. (2014). Three-dimensional Ultrathin Planar Lenses by Acoustic Metamaterials. Scientific Reports, 4(1). doi:10.1038/srep06830 Lan, J., Li, Y., Xu, Y., & Liu, X. (2017). Manipulation of acoustic wavefront by gradient metasurface based on Helmholtz Resonators. Scientific Reports, 7(1). doi:10.1038/s41598-017-10781-5 Jiménez-Gambín, S., Jiménez, N., Benlloch, J. M., & Camarena, F. (2019). Holograms to Focus Arbitrary Ultrasonic Fields through the Skull. Physical Review Applied, 12(1). doi:10.1103/physrevapplied.12.014016 Pérez-López, S., Fuster, J. M., Minin, I. V., Minin, O. V., & Candelas, P. (2019). Tunable subwavelength ultrasound focusing in mesoscale spherical lenses using liquid mixtures. Scientific Reports, 9(1). doi:10.1038/s41598-019-50019-0 Veira Canle, D., Kekkonen, T., Mäkinen, J., Puranen, T., Nieminen, H. J., Kuronen, A., … Hæggström, E. (2019). Practical realization of a s