Showing papers on "Bessel beam published in 1993"
TL;DR: Results show that uniformly high resolutions were obtained with the J0 Bessel beam over a large distance, and Restoration of pulse-echo images obtained with these beams could be simplified.
74 citations
TL;DR: In this paper, the application of a broadband J0 Bessel beam to nonspreading solutions to the isotropic/homogeneous scalar wave equation has been investigated for nondestructive evaluation of materials of different speeds of sound.
36 citations
TL;DR: The characteristics of a so-called nondiffracting beam produced by illumination of a binary-phase reflective holographic optical element with light from a diode laser are reported, which may have application for alignment of integrated optic elements in which unguided diffraction-free beams are used to align glass-slab elements containing interconnection holograms to a computer board.
Abstract: We report for the first time, to our knowledge, the characteristics of a so-called nondiffracting beam produced by illumination of a binary-phase reflective holographic optical element with light from a diode laser. The Bessel beam has an intensity profile whose pattern changes little over distances of order 1 m and has a 1/e amplitude radius for the central lobe of ∼100 µm. This beam may have application for alignment of integrated optic elements in which unguided diffraction-free beams are used to align glass-slab elements containing interconnection holograms to a computer board. The aligning Bessel beam would be produced on reflection from a hologram on the glass-substrate interconnecting element. A single hologram may be used for different substrates having different lengths and functionality because of the large depth of field of the Bessel beam.
32 citations
TL;DR: A two-element refracting system is designed to transform a Gaussian laser beam into a diffraction-free Bessel beam because the resulting input and output surfaces are almost spherical.
Abstract: A two-element refracting system is designed to transform a Gaussian laser beam into a diffraction-free Bessel beam. The resulting input and output surfaces are almost spherical, which makes for easy implementation of the system.
25 citations
01 Jan 1993
TL;DR: In this paper, a generalization of the limited diffraction beams and their applications to medical ultrasonic imaging, biological tissue characterization, and ultrasonic nondestructive evaluation of materials have also been reported.
Abstract: Since the first discovery of localized waves (focused wave mode) in 19831 and limited diffraction beams (Bessel beams) in 1987,2 great advancement in both theory and experiment of these beams have been achieved.3–6 Generalization of the limited diffraction beams and their applications to medical ultrasonic imaging, biological tissue characterization, and ultrasonic nondestructive evaluation of materials have also been reported.7–15
15 citations
TL;DR: In this article, the authors describe the acoustic fields radiated from Bessel beam transducers with an annular ring array, and calculate the fields without the para-axial approximation such as the Fresnel one, in order to elucidate the near fields from the transducers.
Abstract: This paper describes acoustic fields radiated from Bessel beam transducers with an annular ring array. We calculate the fields without the para-axial approximation such as the Fresnel one, in order to elucidate the near fields from the transducers. We find that field intensities from some transducers abruptly increase and decrease in the near region. This makes the transducers inappropriate for imaging applications. Annular transducer elements of width less than 1 wavelength prove to be effective in avoiding the abrupt changes.
10 citations
TL;DR: In this paper, the Bessel beam propagation characteristics were investigated in the presence of azimuthally dependent phase variations of its angular components, and the phase variations influence the beam symmetry and strongly reduce an axial intensity.
Abstract: The Bessel beam propagation characteristics are investigated in the presence of azimuthally dependent phase variations of its angular components. The phase variations influence the beam symmetry and strongly reduce an axial intensity. An experimental interpretation of presented results is also discussed.
8 citations
31 Oct 1993
TL;DR: In this article, the propagation of Bessel beams and X waves in attenuating media, like soft tissues, was investigated, and it was concluded that while Bessel beam can be considered as limited diffraction beam in soft tissue, such assumption is not true for X waves, unless when narrowband signals are used.
Abstract: Recently, diffraction limited beams have received increased attention for use in imaging and material characterization. Properties of two particular types, Bessel beams and the X waves, in lossless media have been reported. In medical applications, however, the propagation media are highly attenuative. The authors investigate propagation of Bessel beams and X waves in attenuating media, like soft tissues. In both cases, field of infinite aperture (ideal beam) and field of finite aperture (practical beam) have been studied. Pulsed beams, which are of interest in pulse echo applications, have been included in the authors' studies. Results show that Bessel beams do not spread laterally in attenuating media. In contrast, the X waves spread rapidly in such media. Lateral spreading of wideband X waves is linearly proportional to the depth and the attenuation coefficient. Spreading rate is lower for narrowband beams. It is concluded that while Bessel beam can be considered as limited diffraction beam in soft tissues, such assumption is not true for X waves, unless when narrowband signals are used
3 citations
14 Sep 1993
TL;DR: In this paper, the authors report the characteristics of the first high efficiency generation of a non-diffracting Bessel beam using a laser diode and a reflective holographic element.
Abstract: We report the characteristics of, to our knowledge, the world's first high efficiency generation of a so-called "non-diffracting" Bessel beam using a laser diode and a reflective holographic element. The beam has a central spot of 200 pm diameter and this spot size is maintained over a propagation distance approaching 1 meter. We consider two free-space optical interconnection schemes which take advantage of the unique characteristics of Bessel beams. >
1 citations
26 Jul 1993
Abstract: This paper investigates image forming properties of the Bessel Beam (Jo ( ar)) and the Absolute-Bessel Beam (!Jo (a r) I) for an aberrated(/aberration-free) optical system. Whilst the Bessel Beam acts as combined filter of ,amplitude and phase(CFAP), the Absolute-Bessel Beam behaves as an amplitude filter only. The Bessel Beam shows superb compensating effect for an optical system with spherical aberration and represents the gain, G is 1.605. This result can therefore be applied to fabrication of semiconductor device.
TL;DR: In this article, the physical properties of diffractionless beams, their propagation and transformation through optical systems are discussed, and numerical calculations are performed to illustrate and compare the characteristics of truncated Bessel beams propagating through a sharp-edged aperture and a soft-edged one.
Abstract: The purpose of this paper is to discuss the physical properties of diffractionless beams, their propagation and transformation through optical systems. We start from the analysis of Durnin’s experiment to present a useful idea for the design of Bessel beam convertors. Then, the propagation of Bessel beams through ABCD optical systems are studied, and numerical calculations are performed to illustrate and compare the characteristics of truncated Bessel beams propagating through a sharp-edged aperture and a soft-edged one.