Birefringence-induced bifocusing for selection of radially or azimuthally polarized laser modes

Machavariani, G.; Lumer, Yaakov; Moshe, Inon; Meir, Avi; Jäckel, S.; Davidson, Nir

doi:10.1364/ao.46.003304

Cited by 80 publications

(36 citation statements)

References 26 publications

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“…It is well-known the usage of anisotrophic elements to convert beams with the homogeneous polarization into cylindrical vector beams [1][2][3][4][5][6]. At the same time, it is necessary to implement the separation of the longitudinal modes along the optical axis of the system, which is parallel to the axis of the crystal.…”

Section: Introductionmentioning

confidence: 99%

Experimantal oberving of transformation Bessel beam spreading along axis of crystal during wavelength changes

Vasilev¹,

Подлипнов²

2017

Collection of Selected Papers of the III International Conference on Information Technology and Nanotechnology

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In paper decribe experimental observing transform bessel beam, formed by diffraction axicon in moment propagation through anisortopic birefringence crystal. This observation covers large range wavelength changes (from 520 nm to 534 nm). Theoretical explain effect is given.Keywords: laser with changing wavelength; diffraction axicon; birefringent crystal; bessel beams IntroductionIt is well-known the usage of anisotrophic elements to convert beams with the homogeneous polarization into cylindrical vector beams [1][2][3][4][5][6]. At the same time, it is necessary to implement the separation of the longitudinal modes along the optical axis of the system, which is parallel to the axis of the crystal. To improve convergence of the beams in the crystal, it is possible to use telescopic system or to form beams with high numerical aperture. Polarization and mode conversion during propagation along the axis of the crystal were considered for both Bessel and Gaussian beams [7][8][9][10][11][12][13][14][15][16].It has been shown in the studies [17,18] that during the propagation along the crystal axis neuraxial Bessel beams have other properties than Gaussian beams, namely, experiencing a uniform periodic change of intensity. In this case, the Bessel beam of zero order and second-order are periodically converted from one to another [7-9, 17, 18]. The oscillation period is directly proportional to the wavelength of the laser radiation and inversely proportional to the square of the spatial frequency of the laser beam and the difference of the dielectric capacitivity, which is corresponding to the ordinary and extraordinary rays. This dependence allows control occurring transformation in the crystal due to changes of the characteristics in either Bessel beam or crystal. In particular, the spatial frequency of the beam depends on the numerical aperture of the axicon [19][20][21][22] which shapes the beam, also it is possible to adjust characteristics of the beam by changing the beam divergence [23]. To change the parameters of the crystal, it can be heated [24] or effected by electro-optic [25]. However, the most convenient way of adjustment is to change the wavelength of the laser radiation which has a direct linear relationship from the period of transformation [26].It was experimentally demonstrated the ability [26] to manage the transformation of the Bessel beam at the output of the CaCO3 crystal by changing the wavelength of the radiation illuminating the diffractive axicon. It was achieved almost complete transformation of the Bessel beam of zero order beam to the second order using the axicon period of 2 µm and the wavelength at Δλ =1.5 of the initial value of λ = 637.5. The variation of the wavelength within a small range was achieved by changing the temperature of the laser. In contrast to this method, the usage of a laser with variable wavelength provides a wide range of Δλ, and therefore the possibility of achieving complete conversion using the axicon with a large period, i.e., a smaller numerical apertur...

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Section: Introductionmentioning

confidence: 99%

Experimantal oberving of transformation Bessel beam spreading along axis of crystal during wavelength changes

Vasilev¹,

Подлипнов²

2017

Collection of Selected Papers of the III International Conference on Information Technology and Nanotechnology

View full text Add to dashboard Cite

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“…It was shown in [6,7,[11][12][13] that when propagating along the crystal axis, nonparaxial Bessel beams undergo a periodic change in intensity, corresponding to a transformation into a higher-order beam. In publications [14][15][16][17][18][19][20], polarization transformations of beams focused along the crystal axis were considered.…”

Section: Introductionmentioning

confidence: 99%

Amplitude and polarization transformations of the Bessel beam as it passes through an anisotropic crystal perpendicular to the axis of the crystal

Glazkova¹,

Zablovskaya²,

Подлипнов³

2017

Collection of Selected Papers of the III International Conference on Information Technology and Nanotechnology

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Amplitude and polarization transformations of the Bessel beam as it passes through an anisotropic crystal perpendicular to the axis of the crystal AbstractA comparative numerical calculation of the propagation of a zero-order Bessel laser beam in a uniaxial crystal perpendicular to its axis is performed using the Rayleigh-Sommerfeld integral operator, generalized for an anisotropic environment. Numerical simulation is performed with a different type of beam polarization and different characteristics of the Bessel beam. Patterns of the beam intensity during the passing of different distances in the crystal are obtained, showing the degree of astigmatic transformation, which makes it possible to determine the conditions under which the greatest astigmatic distortion of the beams occurs. The above analysis can be useful in practice for determining the anisotropy characteristics of a crystal.

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“…Many methods have been reported to generate such beams, mainly including intra-cavity approaches and extra-cavity approaches. In the intra-cavity approaches, the laser resonator itself is modified in a way that the transverse mode exhibits the desired radial profile [2,3] . In the extra-cavity approach, the laser output is manipulated through a combination of suitable optical elements, such as spirally varying optical activity [4] , segmented subwavelength metallic gratings [5] and spatial light modulators [6] .…”

Section: Introductionmentioning

confidence: 99%

Micro-hole fabrication based on focus-shaped radially polarized beams

Zhou

Zhang

et al. 2013

Eighth International Symposium on Precision Engineering Measurement and Instrumentation

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A micro-hole fabrication scheme based on focus-shaped radially polarized beams is presented. First, a micro-hole fabrication system is demonstrated based on the focus shaping of radially polarized beams, where a high energy ultra-small spot with a long depth of focus can be obtained by focus shaping using the combination of a diffractive optical element (DOE) and a high numerical-aperture objective, and such focused spot is preferred to fabricate the micro-hole with a high ratio of depth and radius. Then, diffractive optical elements (DOEs) are designed to achieve such ultra-small spots with a long depth of focus using the global search algorithm, and the focus-shaped field intensities are calculated based on vector diffraction theory. Finally, a conclusion is drawn from the theoretical analysis and numerical simulation, and focus-shaped radially polarized beams are suitable to fabricate the micro-hole with a high ratio of depth and radius.

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Birefringence-induced bifocusing for selection of radially or azimuthally polarized laser modes

Cited by 80 publications

References 26 publications

Experimantal oberving of transformation Bessel beam spreading along axis of crystal during wavelength changes

Experimantal oberving of transformation Bessel beam spreading along axis of crystal during wavelength changes

Amplitude and polarization transformations of the Bessel beam as it passes through an anisotropic crystal perpendicular to the axis of the crystal

Micro-hole fabrication based on focus-shaped radially polarized beams

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