scholarly journals Ag Nanoparticles: Experimental Study of Sign Identification of Nonlinear Refractive Index by Moiré Deflectometry and Z-Scan Methods

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Adeleh Granmayeh Rad ◽  
Khosro Madanipour ◽  
Ata Koohian
Keyword(s):  
Refractive Index ◽  
Ag Nanoparticles ◽  
Nonlinear Refractive Index ◽  
Second Harmonic ◽  
Pure Water ◽  
Nonlinear Effects ◽  
Probe Laser ◽  
Beam Power ◽  
Moiré Fringes ◽  
Moiré Deflectometry

Two different methods are presented for the sign identification of nonlinear refractive index () of Ag colloidal nanoparticles which are based on nonscanning Moiré deflectometry and Z-scan. In the Moiré deflectometry setup, two lasers are used, one is used as pump laser which causes thermal nonlinear effects in the sample, and the second one is used as the probe laser for monitoring these effects by Moiré deflectometry system. By observing the deflected Moiré fringes, we can determine the sign of nonlinear refractive index in real time, and there would be no need for calibration or complicated calculations. The second technique for sign identification is Z-scan. In this technique, a CW 532 nm second harmonic Nd:YAG laser with a beam power of 55 mW is used as the excitation source. Results show that the nonlinear refractive index is negative for Ag nanoparticles in pure water by both methods.

NON-LINEAR REFRACTIVE INDEX MEASUREMENT OF (2E)-3-[4-(DIMETHYLAMINO)PHENYL]-1-(2,5-DIMETHYLTHIOPHEN-3-YL)PROP-2-EN-1-ONE AND (2E)-3-(3,4-DIMETHOXYPHENYL)-1-(2,5-DIMETHYLTHIOPHEN-3-YL)PROP-2-EN-1-ONE

2011 ◽  
Vol 20 (02) ◽  
pp. 183-191 ◽  
Author(s):  
FRYAD Z. HENARI ◽  
ABDULLAH M. ASIRI
Keyword(s):  
Refractive Index ◽  
Absorption Coefficient ◽  
Nonlinear Absorption ◽  
Nonlinear Refractive Index ◽  
Continuous Wave ◽  
Nonlinear Effects ◽  
Optical Limiting ◽  
Nonlinear Absorption Coefficient ◽  
Refractive Index Measurement ◽  
Index Measurement

We report results from investigations of the nonlinear refractive index and nonlinear absorption coefficient of (2E)-3-[4-(Dimethylamino)phenyl]-1-(2,5-dimethylthiophen-3-yl)prop-2-en-1-one and (2E)-3-(3,4-Dimethoxyphenyl)-1-(2,5-dimethylthiophen-3-yl) prop-2-en-1-one using Z-scan technique with a continuous wave (cw) laser at wavelengths 488 nm and 514 nm. The nonlinear refractive index and nonlinear absorption coefficient of both samples were evaluated. The origin of the nonlinear effects was discussed. Optical limiting based on light induced nonlinear refractive index variation is demonstrated. The limiting thresholds were estimated for both samples. The results suggested that these materials offer promise as candidates for optical limiting and optical devices in the low power regime.

Optical Transport Network

2015 ◽  
pp. 28-58
Keyword(s):  
Refractive Index ◽  
Nonlinear Refractive Index ◽  
Power Level ◽  
Nonlinear Effects ◽  
Optical Signal ◽  
Stimulated Scattering ◽  
Optical Signals ◽  
Optical Transport Network ◽  
Scattering Effects

The purpose of this chapter is to discuss two major categories of nonlinear effects related either to nonlinear refractive index or to nonlinear stimulated scattering effects. The effects related to nonlinear refractive index occur due to the dependence of the refractive index on the optical signal intensity. On the other hand, stimulated scattering effects are caused by interaction between light and material. As many wavelength signal channels travel through the optical fiber, they encounter many of those nonlinear effects impairments that affect the signal power level and hence degrade sharply the quality of the signal resulting in interference among signals carried by different wavelength channels. Therefore, before delving into the optical transmission performance issues, a physical picture of how optical signals behave in the presence of the most important nonlinear effect impairments is drawn.

scholarly journals Diffraction Rings Pattern and Nonlinear Optical Properties of Hybrid ZnO-NPs / Epoxy Resin

2020 ◽  
Vol 38 (3A) ◽  
pp. 440-445
Author(s):  
Zahraa M. AL-Asady ◽  
Ali H. AL-Hamdani
Keyword(s):  
Refractive Index ◽  
Absorption Coefficient ◽  
Epoxy Resin ◽  
Nonlinear Absorption ◽  
Nonlinear Refractive Index ◽  
Second Harmonic ◽  
Nonlinear Absorption Coefficient ◽  
Zno Nps ◽  
Nano Composite ◽  
Single Beam

In this research, the diffraction ring patterns scan and single-beam Z-scan techniques were used to measure the nonlinear refractive index (n2) and nonlinear absorption coefficient (β). Nano-composite sample, which consists of zinc oxide nanoparticles (ZnO-NPs), and epoxy resin polymer. The sample was prepared by the casting method. A second harmonic generation Nd: YAG laser, which operates at 532 nm and intensity 3183 W/cm2 was used for the two techniques. Z-scan results showed that values for nonlinear refractive index n2 and nonlinear absorption coefficient β were obtained of 6.59*10-9 cm2/W and 1.75*10-3 cm/W respectively. While results for the D-scan technique showed that the number of rings increases with the increasing of laser power.

NONLINEAR EFFECTS IN ERBIUM-DOPED FIBRES

1993 ◽  
Vol 02 (03) ◽  
pp. 401-413 ◽  
Author(s):  
P.L. CHU ◽  
Y.L. XUE
Keyword(s):  
Refractive Index ◽  
Excited State ◽  
Transient Response ◽  
Ground State ◽  
Nonlinear Refractive Index ◽  
Nonlinear Effects ◽  
Experimental Investigations ◽  
Signal Power ◽  
Switching Speed ◽  
Erbium Doped

Theoretical and experimental investigations of the nonlinear refractive index in an Erbium-doped fibre is presented. The transient response of this fibre is also examined. The switching speed can be improved by using a signal power at a wavelength close to the resonant wavelength between the excited state and the ground state.

Investigating the Nonlinear Optical Response of Pepper Oil under Low Power Irradiation with Continuous Wave Visible Laser Beam

2020 ◽  
pp. 131-138
Keyword(s):  
Refractive Index ◽  
Nonlinear Refractive Index ◽  
Nonlinear Optical ◽  
Continuous Wave ◽  
Diffraction Integral ◽  
Visible Laser ◽  
Limiting Property ◽  
Kirchhoff Diffraction Integral ◽  
Theoretical Results ◽  
Good Agreement

The nonlinear optical properties of pepper oil are studied by diffraction ring patterns and Z-scan techniques with continuous wave beam from solid state laser at 473 nm wavelength. The nonlinear refractive index of the sample is calculated by both techniques. The sample show high nonlinear refractive index. Based on Fresnel-Kirchhoff diffraction integral, the far-field intensity distributions of ring patterns have been calculated. It is found that the experimental results are in good agreement with the theoretical results. Also the optical limiting property of pepper oil is reported. The results obtained in this study prove that the pepper oil has applications in nonlinear optical devices.

scholarly journals Electrically Induced Liquid–Liquid Phase Transition in a Floating Water Bridge Identified by Refractive Index Variations

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 602
Author(s):  
Elmar C. Fuchs ◽  
Jakob Woisetschläger ◽  
Adam D. Wexler ◽  
Rene Pecnik ◽  
Giuseppe Vitiello
Keyword(s):  
Phase Transition ◽  
Refractive Index ◽  
Liquid Phase ◽  
Pure Water ◽  
Resonance Effect ◽  
Water Bridge ◽  
Liquid Phase Transition ◽  
Light Passing ◽  
Floating Water Bridge ◽  
Set Up

A horizontal electrohydrodynamic (EHD) liquid bridge (also known as a “floating water bridge”) is a phenomenon that forms when high voltage DC (kV·cm−1) is applied to pure water in two separate beakers. The bridge, a free-floating connection between the beakers, acts as a cylindrical lens and refracts light. Using an interferometric set-up with a line pattern placed in the background of the bridge, the light passing through is split into a horizontally and a vertically polarized component which are both projected into the image space in front of the bridge with a small vertical offset (shear). Apart from a 100 Hz waviness due to a resonance effect between the power supply and vortical structures at the onset of the bridge, spikes with an increased refractive index moving through the bridge were observed. These spikes can be explained by an electrically induced liquid–liquid phase transition in which the vibrational modes of the water molecules couple coherently.

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