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Nematicons and their electro-optic control: light localization and signal readdressing via reorientation in liquid crystals.

Piccardi A, Alberucci A, Assanto G - Int J Mol Sci (2013)

Bottom Line: Liquid crystals in the nematic phase exhibit substantial reorientation when the molecules are driven by electric fields of any frequencies.Moreover, they can be effectively deviated by using the electro-optic response of the medium, leading to several strategies for voltage-controlled reconfiguration of light-induced guided-wave circuits and signal readdressing.Hereby, we outline the main features of nematicons and review the outstanding progress achieved in the last twelve years on beam self-trapping and electro-optic readdressing.

View Article: PubMed Central - PubMed

Affiliation: Nonlinear Optics and OptoElectronics Lab (NooEL), University of Rome "Roma Tre", Via della Vasca Navale 84, Rome 00146, Italy. assanto@uniroma3.it.

ABSTRACT
Liquid crystals in the nematic phase exhibit substantial reorientation when the molecules are driven by electric fields of any frequencies. Exploiting such a response at optical frequencies, self-focusing supports transverse localization of light and the propagation of self-confined beams and waveguides, namely "nematicons". Nematicons can guide other light signals and interact with inhomogeneities and other beams. Moreover, they can be effectively deviated by using the electro-optic response of the medium, leading to several strategies for voltage-controlled reconfiguration of light-induced guided-wave circuits and signal readdressing. Hereby, we outline the main features of nematicons and review the outstanding progress achieved in the last twelve years on beam self-trapping and electro-optic readdressing.

Show MeSH
Beam propagation in three (undoped) NLC mixtures. As birefringence goes up, walk-off increases, whereas self-confinement is appreciable at lower powers. The rightmost graphs plot linear (dashed line) and nonlinear (solid line, corresponding to the highest excitation) output beam profiles across y.
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f4-ijms-14-19932: Beam propagation in three (undoped) NLC mixtures. As birefringence goes up, walk-off increases, whereas self-confinement is appreciable at lower powers. The rightmost graphs plot linear (dashed line) and nonlinear (solid line, corresponding to the highest excitation) output beam profiles across y.

Mentions: Experimental observations with various NLC mixtures, carried out to underline the role of material parameters, confirmed the theoretical predictions: Figure 4 shows the images acquired from three identical samples filled with distinct NLC, namely 1550, E7 and 1791A [26]. At λ = 1064 nm, they exhibit Δn = n// −n⊥ = 0.05, 0.2 and 0.4, respectively, all with n⊥ ≈ 1.5; consistently, the corresponding measured walk-off angles were δ = 2.5º, 6.5º and 12º, respectively. The input powers required for self-trapping were P = 45, 2 and 0.8 mW, respectively, i.e., the larger n2 is, the lower the excitation needed for nematicon formation.


Nematicons and their electro-optic control: light localization and signal readdressing via reorientation in liquid crystals.

Piccardi A, Alberucci A, Assanto G - Int J Mol Sci (2013)

Beam propagation in three (undoped) NLC mixtures. As birefringence goes up, walk-off increases, whereas self-confinement is appreciable at lower powers. The rightmost graphs plot linear (dashed line) and nonlinear (solid line, corresponding to the highest excitation) output beam profiles across y.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3821595&req=5

f4-ijms-14-19932: Beam propagation in three (undoped) NLC mixtures. As birefringence goes up, walk-off increases, whereas self-confinement is appreciable at lower powers. The rightmost graphs plot linear (dashed line) and nonlinear (solid line, corresponding to the highest excitation) output beam profiles across y.
Mentions: Experimental observations with various NLC mixtures, carried out to underline the role of material parameters, confirmed the theoretical predictions: Figure 4 shows the images acquired from three identical samples filled with distinct NLC, namely 1550, E7 and 1791A [26]. At λ = 1064 nm, they exhibit Δn = n// −n⊥ = 0.05, 0.2 and 0.4, respectively, all with n⊥ ≈ 1.5; consistently, the corresponding measured walk-off angles were δ = 2.5º, 6.5º and 12º, respectively. The input powers required for self-trapping were P = 45, 2 and 0.8 mW, respectively, i.e., the larger n2 is, the lower the excitation needed for nematicon formation.

Bottom Line: Liquid crystals in the nematic phase exhibit substantial reorientation when the molecules are driven by electric fields of any frequencies.Moreover, they can be effectively deviated by using the electro-optic response of the medium, leading to several strategies for voltage-controlled reconfiguration of light-induced guided-wave circuits and signal readdressing.Hereby, we outline the main features of nematicons and review the outstanding progress achieved in the last twelve years on beam self-trapping and electro-optic readdressing.

View Article: PubMed Central - PubMed

Affiliation: Nonlinear Optics and OptoElectronics Lab (NooEL), University of Rome "Roma Tre", Via della Vasca Navale 84, Rome 00146, Italy. assanto@uniroma3.it.

ABSTRACT
Liquid crystals in the nematic phase exhibit substantial reorientation when the molecules are driven by electric fields of any frequencies. Exploiting such a response at optical frequencies, self-focusing supports transverse localization of light and the propagation of self-confined beams and waveguides, namely "nematicons". Nematicons can guide other light signals and interact with inhomogeneities and other beams. Moreover, they can be effectively deviated by using the electro-optic response of the medium, leading to several strategies for voltage-controlled reconfiguration of light-induced guided-wave circuits and signal readdressing. Hereby, we outline the main features of nematicons and review the outstanding progress achieved in the last twelve years on beam self-trapping and electro-optic readdressing.

Show MeSH