Effect of residual phase gradients in optical null interference

Naik, Dinesh N.; Chakravarthy, T. Pradeep; Viswanathan, Nirmal K.

doi:10.1364/ol.41.000092

Cited by 4 publications

(3 citation statements)

References 14 publications

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“…The splitting rotates to the horizontal plane at the Brewster angle and then towards the nearly vertical plane −45°(upper half) and 45°(lower half) but in a reversed way. This polarizationdependent beam-rotation behavior around the Brewster angle is reminiscent of field-rotation around singularities and in null-interferometers [33]. For LG beams in the second, third and forth rows, we have observed a similar rotation effect and additional spiraling behavior whose magnitude increases with the mode of LG beams.…”

Section: Discussion Of Resultssupporting

confidence: 66%

Observation of diffractive-correction and spin-orbit interaction induced effects around the Brewster angle

Prajapati

Viswanathan

2019

J. Opt.

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We report the observation of splitting, rotation and spiraling behavior in the polarization components of the Laguerre–Gaussian beam, reflected around the Brewster angle for a TM-polarized input beam. The measurements carried out using Stokes parameters in addition show that the strength and behavior of the above-mentioned effects depend on the order of the Laguerre–Gaussian beam. These polarization effects appear to be a manifestation of the collaborative behavior of the diffraction-corrective longitudinal Goos–Hänchen and spin-orbit interaction induced transverse spin-Hall shifts, wherein the coupling between these shifts play a critical role. Except for the polarization splitting, other observed effects are absent for a TE polarized input beam. These studies are useful to understand the topological aspect of complex light field in various applications, including optical manipulation, wherein the source optical angular momentum has been point of discussion. Additionally, they can be used as a promising tool in the identification of the thickness of thin layer and optical sensing.

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Section: Discussion Of Resultssupporting

confidence: 66%

Observation of diffractive-correction and spin-orbit interaction induced effects around the Brewster angle

Prajapati

Viswanathan

2019

J. Opt.

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“…As mentioned earlier, different approaches are designed to compensate or overcome it. In the proposed interferometric approach of introducing lateral shear and linear phase difference in orthogonal directions between superposing out-of-phase Gaussian beams, a hinge-point thus appearing plays a crucial role 61 . The source of achromatic nature of the generated vortex can be easily understood from the well-known optical white-light interferometry.…”

Section: Discussionmentioning

confidence: 99%

Ultrashort vortex from a Gaussian pulse – An achromatic-interferometric approach

Naik

Saad

Rao

et al. 2017

Sci Rep

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The more than a century old Sagnac interferometer is put to first of its kind use to generate an achromatic single-charge vortex equivalent to a Laguerre-Gaussian beam possessing orbital angular momentum (OAM). The interference of counter-propagating polychromatic Gaussian beams of beam waist ωλ with correlated linear phase (ϕ 0 ≥ 0.025 λ) and lateral shear (y 0 ≥ 0.05 ωλ) in orthogonal directions is shown to create a vortex phase distribution around the null interference. Using a wavelength-tunable continuous-wave laser the entire range of visible wavelengths is shown to satisfy the condition for vortex generation to achieve a highly stable white-light vortex with excellent propagation integrity. The application capablitiy of the proposed scheme is demonstrated by generating ultrashort optical vortex pulses, its nonlinear frequency conversion and transforming them to vector pulses. We believe that our scheme for generating robust achromatic vortex (implemented with only mirrors and a beam-splitter) pulses in the femtosecond regime, with no conceivable spectral-temporal range and peak-power limitations, can have significant advantages for a variety of applications.

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“…From our recent investigations on optical null interference using Gaussian beams, we found that there is a more fundamental picture to the interferometric generation of an optical singularity beyond the view as a vortex array generator. The recent study on optical null interference has exemplified the role played by a pivot point in a two-Gaussian beam interference where the phase remains stationary and surrounding optical field undergoes a rotation in the presence of a phase ramp [24,25]. It is well known that the vortices are created and annihilated as dipoles.…”

Section: Introductionmentioning

confidence: 99%

Generation of singular optical beams from fundamental Gaussian beam using Sagnac interferometer

Naik

Viswanathan

2016

J. Opt.

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We propose a simple free-space optics recipe for the controlled generation of optical vortex beams with a vortex dipole or a single charge vortex, using an inherently stable Sagnac interferometer. We investigate the role played by the amplitude and phase differences in generating higher-order Gaussian beams from the fundamental Gaussian mode. Our simulation results reveal how important the control of both the amplitude and the phase difference between superposing beams is to achieving optical vortex beams. The creation of a vortex dipole from null interference is unveiled through the introduction of a lateral shear and a radial phase difference between two out-of-phase Gaussian beams. A stable and high quality optical vortex beam, equivalent to the first-order Laguerre–Gaussian beam, is synthesized by coupling lateral shear with linear phase difference, introduced orthogonal to the shear between two out-of-phase Gaussian beams.

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Effect of residual phase gradients in optical null interference

Cited by 4 publications

References 14 publications

Observation of diffractive-correction and spin-orbit interaction induced effects around the Brewster angle

Observation of diffractive-correction and spin-orbit interaction induced effects around the Brewster angle

Ultrashort vortex from a Gaussian pulse – An achromatic-interferometric approach

Generation of singular optical beams from fundamental Gaussian beam using Sagnac interferometer

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