Strong on-axis focal shift and its nonlinear variation in low-Fresnel-number ultrasound beams

2006 ◽  
Vol 119 (6) ◽  
pp. 3618-3624 ◽  
Author(s):  
Y. N. Makov ◽  
V. Espinosa ◽  
V. J. Sánchez-Morcillo ◽  
J. Ramis ◽  
J. Cruañes ◽  
...  
Keyword(s):  
Fresnel Number ◽  
Nonlinear Variation ◽  
Focal Shift

Strong on-axis focal shift and its nonlinear variation in low-fresnel-number ultrasound beams

2006 ◽  
Author(s):  
Y.N. Makov ◽  
V. Espinosa ◽  
V.J. Sanchez-Morcillo ◽  
J. Ramis ◽  
J. Cruanes ◽  
...  
Keyword(s):  
Fresnel Number ◽  
Nonlinear Variation ◽  
Focal Shift

Effective Fresnel-number concept for evaluating the relative focal shift in focused beams

1998 ◽  
Vol 15 (2) ◽  
pp. 449 ◽  
Author(s):  
Manuel Martı́nez-Corral ◽  
Carlos J. Zapata-Rodrı́guez ◽  
Pedro Andrés ◽  
Enrique Silvestre
Keyword(s):  
Fresnel Number ◽  
Number Concept ◽  
Focal Shift ◽  
Focused Beams

Focusing properties and focal shift of a vortex cosine-hyperbolic Gaussian beam

2021 ◽  
Author(s):  
Zoubir Hricha ◽  
El Mostapha El Halba ◽  
Mohammed Lazrek ◽  
Abdelmajid Belafhal
Keyword(s):  
Incident Beam ◽  
Beam Width ◽  
Spot Size ◽  
Fresnel Number ◽  
Beam Focusing ◽  
Diffraction Integral ◽  
Focal Shift ◽  
Beam Parameters ◽  
Focus Plane ◽  
Focusing Properties

Abstract In this paper, we investigate the focusing properties of a vortex-cosh-Gaussian (vChG) beam passing through a converging thin lens. Based on the Huygens-Fresnel diffraction integral, we derived the analytical propagation equation as well as the beam width expression of a focused vChGB. It is shown that the focusing properties including the focal shift of the focused vChGB are crucially dependent on the incident beam parameters namely the decentered parameter and the topological charge in addition to the Gaussian Fresnel number\({N_F}\). From typical numerical examples, it is found that the focused vChGB is transformed into a multi-lobes structure shape at the real focus plane, and the principal maximum intensity of the beam is located away from the axis. The amount of focal shift, which is determined from the minimum spot size criterion, is strongly dependent on the Fresnel number, the decentered parameter and the vortex charge m. The obtained results may be useful for the applications of the vChGBs in beam shaping and beam focusing.

Nonlinear focal shift in medium Fresnel-number focused acoustic beams

2010 ◽  
Author(s):  
Francisco Camarena ◽  
Yuri Makov ◽  
Victor Sanchez-Morcillo ◽  
Silvia Adrian ◽  
Noe Jimenez
Keyword(s):  
Fresnel Number ◽  
Acoustic Beams ◽  
Focal Shift

Dependence of focal shift on Fresnel number and angular aperture

1998 ◽  
Vol 23 (23) ◽  
pp. 1803 ◽  
Author(s):  
C. J. R. Sheppard ◽  
P. Török
Keyword(s):  
Angular Aperture ◽  
Fresnel Number ◽  
Focal Shift

Nonlinear focal shift in focused ultrasonic transducers and its dependence on the Fresnel number

2008 ◽  
Vol 123 (5) ◽  
pp. 3848-3848
Author(s):  
Yuri Makov ◽  
Victor Sánchez‐Morcillo ◽  
Francisco Camarena ◽  
Víctor Espinosa
Keyword(s):  
Ultrasonic Transducers ◽  
Fresnel Number ◽  
Focal Shift
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