Tunable depth of focus of acoustical pupil masked Soret Zone Plate

Abstract In acoustical lenses both resolution and depth of focus are determined by diffraction and the smaller the lens aperture the worse the resolution and the greater the depth of focus. Diffraction-limited resolution has a Soret Zone Plate, but a long depth of focus has an axicon. Nevertheless, these are two different devices each of which requires its own independent design. In this paper, we have shown that the transition from focusing to a diffraction limited spot to a quasi-diffraction free beam can be realized in the same focusing device without changing its topology. It has been shown that using a classical planar Soret Zone Plate lens made of a concentric array of circular aperiodical rings with an amplitude pupil mask placed closely to the surface of lens allows to form a quasi-Bessel beams under specific conditions, part of a diffracted wave collimates, producing an elongated focus. Experiments are performed in water tanks in order to verify the simulation results. Experimental verification shown that the depth of focus of a pupil-masked Soret Zone Plate increases 1.63 times and resolution increases 1.2 times (with minimal beam waist about of 0.67 of wavelength and depth of focus about 5.72 of wavelength). By dynamically controlling the size of the amplitude pupil mask, it is possible to quickly control the depth of focus of an acoustic lens.

[1]  Antonio Uris,et al.  An Ultrasonic Lens Design Based on Prefractal Structures , 2016, Symmetry.

[2]  Heinz Hoffmann,et al.  Ultrasound Axicon: a device for focusing over a large depth , 1973 .

[3]  Michael Nicholas,et al.  Thin Fresnel zone plate lenses for focusing underwater sound , 2015 .

[4]  Nikolay I. Zheludev,et al.  Point spread function of the optical needle super-oscillatory lens , 2014 .

[5]  R. W. Wood,et al.  LIII. Phase-reversal zone-plates, and diffraction-telescopes , 1898 .

[6]  Hiroshi Shimizu,et al.  Planar-structure focusing lens for acoustic microscope , 1991 .

[7]  I. Golub,et al.  Toward the subdiffraction focusing limit of optical superresolution. , 2007, Optics letters.

[8]  Eun Sok Kim,et al.  Microfluidic motion generation with acoustic waves , 1998 .

[9]  David K. Hsu,et al.  Bessel beam ultrasonic transducer: Fabrication method and experimental results , 1989 .

[11]  I. V. Minin,et al.  3D High-Quality Ultrasonic Imaging , 2011 .

[12]  J. M. Fuster,et al.  Pinhole Zone Plate Lens for Ultrasound Focusing , 2017, Sensors.

[13]  Wei Xu,et al.  A flat acoustic lens to generate a Bessel‐like beam , 2017, Ultrasonics.

[14]  Michael Nicholas,et al.  Thin Fresnel zone plate lenses for underwater acoustics: Modeling and experiments , 2015, OCEANS 2015 - MTS/IEEE Washington.

[15]  K. Staliunas,et al.  Acoustic Bessel-like beam formation by an axisymmetric grating , 2014, 1401.6769.

[16]  Ruzairi Abdul Rahim,et al.  Sensing Wood Decay in Standing Trees: A Review , 2018 .

[17]  B. A. Auld,et al.  Acoustic Fresnel zone plate transducers , 1974 .

[18]  Kenneth B. Crozier,et al.  Microfabricated water immersion zone plate optical tweezer , 2008 .

[19]  W. Bragg,et al.  The Reflection of X-rays by Crystals , 1913 .

[20]  J. Dyson,et al.  Circular and spiral diffraction gratings , 1958, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.

[21]  Minghui Hong,et al.  Shaping a Subwavelength Needle with Ultra-long Focal Length by Focusing Azimuthally Polarized Light , 2015, Scientific Reports.

[22]  A practical ultrasound axicon for non-destructive testing , 1982 .

[23]  P. Katchadjian,et al.  APPLICATION OF AXICON LENSES IN ULTRASONIC TECHNIQUES , 2010 .

[24]  K. Kwok,et al.  Self-focused acoustic ejectors for viscous liquids. , 2010, The Review of scientific instruments.

[25]  Koichi Mizutani,et al.  Acoustic Beam Scanning Using Annular Transducer Array Introducing Decentering Operation , 2006 .

[26]  Chiara Daraio,et al.  Acoustic Fresnel lenses with extraordinary transmission , 2014 .

[27]  J. Greenleaf,et al.  A study of two-dimensional array transducers for limited diffraction beams , 1994, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[28]  J. L. Soret.  Ueber die durch Kreisgitter erzeugten Diffractionsphänomene , 1875 .