Generation of radially polarized Bessel–Gaussian beams from c-cut Nd:YVO_4 laser

Vyas, Sunil; Kozawa, Yuichi; Sato, Shunichi

doi:10.1364/ol.39.001101

Cited by 39 publications

(11 citation statements)

References 24 publications

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“…The extra-cavity generation of such beams has been achieved by using an interference approach [12,22,23], liquid crystals [24,25], sub-wavelength grating [26] and from a spirally varying retarder [27]. Laser cavities have been customized to produce particular CV beams by techniques such as inducing thermal stress to isotropic gain media [28], by exploiting the thermal birefringence of laser gain media [29][30][31], with the use of an intracavity axicon [32][33][34] and with a conical shaped pump beam [35][36][37]. The poles of the HOP sphere represent scalar vortex beams (having helical wavefronts) with a uniform circular polarization (right circular at the north pole and left circular at the south pole).…”

Section: Introductionmentioning

confidence: 99%

Controlled generation of higher-order Poincaré sphere beams from a laser

et al. 2016

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The angular momentum state of light can be described by positions on a higher-order Poincaré (HOP) sphere, where superpositions of spin and orbital angular momentum states give rise to laser beams that have found many applications, including optical communication, quantum information processing, microscopy, optical trapping and tweezing and materials processing. Many techniques exist to create such beams but none to date allow their creation at the source. Here we report on a new class of laser that is able to generate all states on the HOP sphere. We exploit geometric phase control with a non-homogenous polarization optic and a wave-plate inside a laser cavity to map spin angular momentum (SAM) to orbital angular momentum (OAM). Rotation of these two elements provides the necessary degrees of freedom to traverse the entire HOP sphere. As a result, we are able to demonstrate that the OAM degeneracy of a standard laser cavity may be broken, producing pure OAM modes as the output, and that generalized vector vortex beams may be created from the same laser, for example, radially and azimuthally polarized laser beams. It is noteworthy that all other aspects of the laser cavity follow a standard design, facilitating easy implementation.

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Section: Introductionmentioning

confidence: 99%

Controlled generation of higher-order Poincaré sphere beams from a laser

et al. 2016

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“…However, due to limitations in the physical size of utilizable apertures and available input energy, one can only create approximations of such beams in the laboratory, which are known as quasi-Bessel beams or Bessel-Gauss (BG) beams. Several methods exist to generate vector BG beams including spatial light modulators [6,7], axicons [8,9], or tuning the output mode of a laser [10]. The vectorial behavior of such BG beams is particularly important under tight focusing conditions, where longitudinal electric field components naturally arise [11][12][13][14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Demonstration of longitudinally polarized optical needles

Turquet¹,

Zang²,

Kakko³

et al. 2018

Opt. Express

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Longitudinally polarized optical needles are beams that exhibit ultra-long depth of field, subwavelength transverse confinement, and polarization oriented along the longitudinal direction. Although several techniques have been proposed to generate such needles, their scarce experimental observations have been indirect and incomplete. Here, we demonstrate the creation and full three-dimensional verification of a longitudinally polarized optical needle. This needle is produced by generating a radially polarized Bessel-Gauss beam at the focus of a high numerical aperture microscope objective. Using three-dimensional spatial mapping of second-harmonic generation from a single vertically aligned GaAs nanowire, we directly verify such a longitudinally polarized optical needle's properties, which are formed at the focus. The needle exhibits a dominant polarization, which is oriented along the longitudinal direction, an ultra-long depth of field (30 λ), and high spatial homogeneity. These are in agreement with corresponding focal field calculations that use vector diffraction theory. Our findings open new opportunities for manipulation and utilization of longitudinally polarized optical needles.

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“…Beyond all-dielectric elliptical metasurface array 44 , hybrid dielectric/metal metasurface structure adding metal at the bottom as the reflection layer may further improve the efficiency and bring superior performance. In addition to the passive method of Bessel-Gaussian beam generation through axicon-enabled light beam conversion, an active method of Bessel-Gaussian beam laser is of great interest 45 – 49 . A digital laser with an intra-cavity digitally addressed holographic mirror was proposed and demonstrated with impressive performance for on-demand laser modes, i.e.…”

Section: Introductionmentioning

confidence: 99%

Metasurface-assisted orbital angular momentum carrying Bessel-Gaussian Laser: proposal and simulation

Zhou

Wang

2018

Sci Rep

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Bessel-Gaussian beams have distinct properties of suppressed diffraction divergence and self-reconstruction. In this paper, we propose and simulate metasurface-assisted orbital angular momentum (OAM) carrying Bessel-Gaussian laser. The laser can be regarded as a Fabry-Perot cavity formed by one partially transparent output plane mirror and the other metasurface-based reflector mirror. The gain medium of Nd:YVO4 enables the lasing wavelength at 1064 nm with a 808 nm laser serving as the pump. The sub-wavelength structure of metasurface facilitates flexible spatial light manipulation. The compact metasurface-based reflector provides combined phase functions of an axicon and a spherical mirror. By appropriately selecting the size of output mirror and inserting mode-selection element in the laser cavity, different orders of OAM-carrying Bessel-Gaussian lasing modes are achievable. The lasing Bessel-Gaussian0, Bessel-Gaussian01+, Bessel-Gaussian02+ and Bessel-Gaussian03+ modes have high fidelities of ~0.889, ~0.889, ~0.881 and ~0.879, respectively. The metasurface fabrication tolerance and the dependence of threshold power and output lasing power on the length of gain medium, beam radius of pump and transmittance of output mirror are also discussed. The obtained results show successful implementation of metasurface-assisted OAM-carrying Bessel-Gaussian laser with favorable performance. The metasurface-assisted OAM-carrying Bessel-Gaussian laser may find wide OAM-enabled communication and non-communication applications.

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Generation of radially polarized Bessel–Gaussian beams from c-cut Nd:YVO_4 laser

Cited by 39 publications

References 24 publications

Controlled generation of higher-order Poincaré sphere beams from a laser

Controlled generation of higher-order Poincaré sphere beams from a laser

Demonstration of longitudinally polarized optical needles

Metasurface-assisted orbital angular momentum carrying Bessel-Gaussian Laser: proposal and simulation

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