Non‐Diffracting Waves: An Introduction

Recami, Erasmo; Zamboni‐Rached, Michel; Ambrosio, Leonardo André

doi:10.1002/9783527671519.ch1

Cited by 5 publications

(9 citation statements)

References 132 publications

(413 reference statements)

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“…Closely related to this last point is the issue of selecting the dimensions for the annular radiator: That is, its radius R, the ring widths d, and the spacing (or kerf, ∆ d ) between the rings. One does not have a priori specific criteria for this selection, apart from the "conservative" approach of equation (21) which suggests the minimum possible radius for the aperture.…”

Section: Discussionmentioning

confidence: 99%

“…The sufficient (but not necessary) condition (21) can be derived by setting (β R ) max = ω 0 /c (see Ref. [20]).…”

Section: Acoustical Restrictions For Ultrasonic Fwsmentioning

confidence: 99%

“…[20]). To see the dependence of the emitter radius R min on L and on parameter N , in Fig.3 we show relation (21) at work for two frequencies: f 0 = 1 MHz (dashed lines), and f 0 = 2.5 MHz (thicker lines). Notice how the size required for the radiators are in general bigger than those normally used in laboratory applications (R min > 1 cm).…”

Section: Acoustical Restrictions For Ultrasonic Fwsmentioning

confidence: 99%

“…[58], [59], [60], [62], and Ref. [23], just appeared as Chap.1 in the new book [6]. The FWs have been experimentally generated for the first time, in 2012, in Optics [9]; while computer simulations of the experimental production of ultrasonic FWs have recently yielded promising results [20].…”

Section: Introductionmentioning

confidence: 99%

“…Indeed, the LWs are solutions to the wave equations capable of resisting the effects of diffraction, and in some cases even of attenuation, at least up to a certain distance (depth of field). Such fields, being solutions to the wave equations, can find application in diverse technological areas, in Optics [5], [6], [7], [8], [9], in Acoustics [10], [11], [15], [20], [5], [6], in Geophysics [21], and so on; besides playing interesting theoretical roles, even in special relativity [22], [23], [24], [25], quantum mechanics [26], etc. In a very large number of theoretical and experimental works, such soliton-like solutions to the linear wave equations have been shown to be endowed with peak-velocities V ranging from 0 to ∞; even if they have been extensively studied [5], [6], [7] mainly for their peculiar properties, like their self-recontruction ("self-healing") after obstacles with size much larger than the wavelenght, provided that it be smaller than their antenna, and not at all for their speed.…”

Section: Introductionmentioning

confidence: 99%

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Producing acoustic ‘Frozen Waves’: Simulated experiments with diffraction/attenuation resistant beams in lossy media

Prego-Borges¹,

Zamboni‐Rached²,

Recami³

et al. 2014

Ultrasonics

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The so-called Localized Waves (LW), and the "Frozen Waves" (FW), have raised significant attention in the areas of Optics and Ultrasound, because of their surprising energy localization properties. The LWs resist the effects of diffraction for large distances, and possess an interesting self-reconstruction -self-healing- property (after obstacles with size smaller than the antenna's); while the FWs, a sub-class of LWs, offer the possibility of arbitrarily modeling the longitudinal field intensity pattern inside a prefixed interval, for instance 0⩽z⩽L, of the wave propagation axis. More specifically, the FWs are localized fields "at rest", that is, with a static envelope (within which only the carrier wave propagates), and can be endowed moreover with a high transverse localization. In this paper we investigate, by simulated experiments, various cases of generation of ultrasonic FW fields, with the frequency of f0=1 MHz in a water-like medium, taking account of the effects of attenuation. We present results of FWs for distances up to L=80 mm, in attenuating media with absorption coefficient α in the range 70⩽α⩽170 dB/m. Such simulated FW fields are constructed by using a procedure developed by us, via appropriate finite superpositions of monochromatic ultrasonic Bessel beams. We pay due attention to the selection of the FW parameters, constrained by the rather tight restrictions imposed by experimental Acoustics, as well as to some practical implications of the transducer design. The energy localization properties of the Frozen Waves can find application even in many medical apparatus, such as bistouries or acoustic tweezers, as well as for treatment of diseased tissues (in particular, for the destruction of tumor cells, without affecting the surrounding tissues; also for kidney stone shuttering, etc.).

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Section: Discussionmentioning

confidence: 99%

“…The sufficient (but not necessary) condition (21) can be derived by setting (β R ) max = ω 0 /c (see Ref. [20]).…”

Section: Acoustical Restrictions For Ultrasonic Fwsmentioning

confidence: 99%

Section: Acoustical Restrictions For Ultrasonic Fwsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Producing acoustic ‘Frozen Waves’: Simulated experiments with diffraction/attenuation resistant beams in lossy media

Prego-Borges¹,

Zamboni‐Rached²,

Recami³

et al. 2014

Ultrasonics

Self Cite

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The propagation speed of optical speckle

Wan

Yessenov

Padgett

2023

Sci Rep

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That the speed of light in vacuum is constant is a cornerstone of modern physics. However, recent experiments have shown that when the light field is confined in the transverse plane, the observed propagation speed of the light is reduced. This effect is a consequence of the transverse structure which reduces the component of wavevector of the light in the direction of propagation, thereby modifying both the phase and group velocity. Here, we consider the case of optical speckle, which has a random transverse distribution and is ubiquitous with scales ranging from the microscopic to the astronomical. We numerically investigate the plane-to-plane propagation speed of the optical speckle by using the method of angular spectrum analysis. For a general diffuser with Gaussian scattering over an angular range of 5°, we calculate the slowing of the propagation speed of the optical speckle to be on the order of 1% of the free-space speed, resulting in a significantly higher temporal delay compared to the Bessel and Laguerre–Gaussian beams considered previously. Our results have implications for studying optical speckle in both laboratory and astronomical settings.

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