Flattened light beams with an axial shadow generated through superposing cosh-Gaussian beams

Optik ◽  
2002 ◽  
Vol 113 (5) ◽  
pp. 222-226 ◽  
Author(s):  
Kaicheng Zhu ◽  
Huiqin Tang ◽  
Xuewen Wang ◽  
Tienan Liu
Keyword(s):  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Netanel Biton ◽  
Judy Kupferman ◽  
Shlomi Arnon

AbstractA major challenge in use of the optical spectrum for communication and imaging applications is the scattering of light as it passes through diffuse media. Recent studies indicate that light beams with orbital angular momentum (OAM) can penetrate deeper through diffuse media than simple Gaussian beams. To the best knowledge of the authors, in this paper we describe for the first time an experiment examining transmission of OAM beams through biological tissue with thickness of up to a few centimeters, and for OAM modes reaching up to 20. Our results indicate that OAM beams do indeed show a higher transmittance relative to Gaussian beams, and that the greater the OAM, the higher the transmittance also up to 20, Our results extend measured results to highly multi scattering media and indicate that at 2.6 cm tissue thickness for OAM of order 20, we measure nearly 30% more power in comparison to a Gaussian beam. In addition, we develop a mathematical model describing the improved permeability. This work shows that OAM beams can be a valuable contribution to optical wireless communication (OWC) for medical implants, optical biological imaging, as well as recent innovative applications of medical diagnosis.


Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 221
Author(s):  
Argelia Balbuena Balbuena Ortega ◽  
Felix E. Torres-González ◽  
Valentin López López Gayou ◽  
Raul Delgado Delgado Macuil ◽  
Gaetano Assanto ◽  
...  

We carry out an experimental campaign to investigate the nonlinear self-defocusing propagation of singular light beams with various complex structures of phase and intensity in a colloidal suspension of gold nanoparticles with a plasmonic resonance near the laser wavelength (532nm). Studying optical vortices embedded in Gaussian beams, Bessel vortices and Bessel-cosine (necklace) beams, we gather evidence that while intense vortices turn into two-dimensional dark solitons, all structured wavepackets are able to guide a weak Gaussian probe of different wavelength (632.8 nm) along the dark core. The probe confinement also depends on the topological charge of the singular pump.


2002 ◽  
Vol 207 (1-6) ◽  
pp. 29-34 ◽  
Author(s):  
Kaicheng Zhu ◽  
Huiqin Tang ◽  
Xingming Sun ◽  
Xuewen Wang ◽  
Tienan Liu
Keyword(s):  

Photonics ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 190
Author(s):  
Alexey A. Kovalev ◽  
Victor V. Kotlyar ◽  
Darya S. Kalinkina

We studied paraxial light beams, obtained by a continuous superposition of off-axis Gaussian beams with their phases chosen so that the whole superposition is invariant to free-space propagation, i.e., does not change its transverse intensity shape. Solving a system of five nonlinear equations for such superpositions, we obtained an analytical expression for a propagation-invariant off-axis elliptic Gaussian beam. For such an elliptic beam, an analytical expression was derived for the orbital angular momentum, which was shown to consist of two terms. The first one is intrinsic and describes the momentum with respect to the beam center and is shown to grow with the beam ellipticity. The second term depends parabolically on the distance between the beam center and the optical axis (similar to the Steiner theorem in mechanics). It is shown that the ellipse orientation in the transverse plane does not affect the normalized orbital angular momentum. Such elliptic beams can be used in wireless optical communications, since their superpositions do not interfere in space, if they do not interfere in the initial plane.


2001 ◽  
Vol 48 (2) ◽  
pp. 371-377
Author(s):  
Baida Lü ◽  
Shirong Luo ◽  
Xiaoling Ji

2012 ◽  
Vol 182 (4) ◽  
pp. 442 ◽  
Author(s):  
Vladimir G. Volostnikov
Keyword(s):  

2002 ◽  
Vol 728 ◽  
Author(s):  
Munir H. Nayfeh

AbstractWe dispersed electrochemically etched Si into ultrabright ultrasmall nanoparticles, with brightness higher than fluorescein or rhodamine. The emission from single particles is readily detectable. Aggregates or films of the particles exhibit emission with highly nonlinear characteristics. We observe directed blue beams at ∼ 410 nm between faces of aggregates excited by femtosecond radiation at 780 nm; and at ∼ 610 nm from aggregates of red luminescent Si nanoparticles excited by radiation at 550-570 nm from a mercury lamp. Intense directed Gaussian beams, a pumping threshold, spectral line narrowing, and speckle patterns manifest the emission. The results are analyzed in terms of population inversion and stimulated emission in quantum confinement-induced Si-Si dimer phase, found only on ultrasmall Si nanoparticles. This microlasing constitutes an important step towards the realization of a laser on a chip.


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