Differential interferometric technique for the measurement of the nonlinear index of refraction of ruby and GdAlO_3:Cr^+3

Catunda, T.; Andreeta, José Pedro; Castro, Jarbas C.

doi:10.1364/ao.25.002391

Cited by 48 publications

(14 citation statements)

References 9 publications

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“…We can write the refractive index as n n o Δn, where the refractive index of the unpumped crystal n o (when N ex 0) is given by n 2 o 1 4πf L χ m N t · α pg and f L n 2 o 2∕3 is the Lorenz local field correction factor. The refractive index change Δn is proportional to the susceptibility change due to the excited state population, Δχ Δα p :N ex , and is given by [10] Δn…”

Section: Theoretical Groundmentioning

confidence: 99%

“…In their theoretical analysis, the authors concluded that the refractive index grating, also called the dispersive grating, instead of the absorption grating, gives the dominant contribution to the process. The first quantitative measurement of the nonlinearity in ruby was made using an interferometric technique [10] that conclusively demonstrated the dispersive origin of the phase conjugation, since it was measured that the real part of the refractive index change was 1 order of magnitude larger than the imaginary one. From this result, it was found that the polarizability difference between excited and ground states of ruby is Δα p 1.6 × 10 −25 cm 3 , a value which was later confirmed by several experiments [4,7,[11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

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Optically pump-induced athermal and nonresonant refractive index changes in the reference Cr-doped laser materials: Cr:GSGG and ruby

et al. 2012

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The refractive index of most ion-doped materials increases with the excited state population. This effect was studied in many laser materials, particularly those doped with Cr 3 and rare earth ions, using several techniques, such as interferometry, wave mixing, and Z-scans. This refractive index variation is athermal (has an electronic origin) and is associated with the difference in the polarizabilites of the Cr 3 ion in its excited and ground states, Δα p . The Cr 3 optical transitions in the visible domain are electric-dipole forbidden, and they have low oscillator strengths. Therefore, the major contribution to Δα p has been assigned to allowed transitions to charge transfer bands (CTBs) in the UV with strengths ∼3 orders of magnitude higher. Although this CTB model qualitatively explains the main observations, it was never quantitatively tested. In order to further investigate the physical origin of Δα p in Cr 3 -doped crystals, excited state absorption (ESA) and Z-scan measurements were thus performed in Cr:Al 2 O 3 (ruby) and Cr:GSGG. Cr:GSGG was selected because of the proximity of its 2 E and 4 T 2 emitting levels, and thus the possibility to explore the role of the spin selection rule in the ESA spectra and the resulting variations in polarizability by comparing low and room temperature data, which were never reported before. On the other hand, Cr:Al 2 O 3 (ruby) was selected because it is the only crystal for which it is possible to obtain CTB absorption data from both ground and excited states, and thus for which it is possible to check the CTB model more accurately. Thanks to these more accurate and more complete data, we came to the first conclusion that the spin selection rule does not play any significant role in the variation of the polarizability with the 2 E-4 T 2 energy mismatch. We also discovered that using the CTB model in the case of ruby would lead to a negative Δα p value, which is contrary to all refractive index variation (including Z-scan) measurements.

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Section: Theoretical Groundmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Optically pump-induced athermal and nonresonant refractive index changes in the reference Cr-doped laser materials: Cr:GSGG and ruby

et al. 2012

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“…The former is a time dependent signal proportional to the laser power contained in the peripheral area of the Gaussian laser beam (with width Win the mask plane). (11) fr =AP =A1T(O.O4P), (12) where P is the instantaneous power of the incident laser signal. The next step is to express the ratio V2 I V as a function of the beam divergence e .…”

Section: Experimental Set-upmentioning

confidence: 99%

Experimental and theoretical investigation of a nonlinear lensing effect observed in a Cr:LiSAF laser

Passilly

Fromager

Aı̈t-Ameur

et al. 2004

Solid State Lasers and Amplifiers

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An experiment has been performed to analyse a nonlinear lensing effect in a flashlamp pumped Cr : LiSAF laser which has been found to be a diverging lensing effect. The latter is due to the refractive index change which is assumed to be proportional to the excited ion population. The corresponding constant of proportionality has been measured from the time variation of the laser pulses far-field divergence.

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“…The simplest method to measure the nonlinear optical properties of materials is Z-scan method. Z-scan is a wellestablished method for the determination of nonlinear refraction and absorption and has been widely used in material characterization since it can provide not only the magnitudes of real and imaginary parts of nonlinear susceptibility, but also their signs (Yang et al 2004;Catunda et al 1986;Tingchao et al 2008;He et al 1997). In this method, the sample is scanned along the propagation path of a focus the Gaussian laser.…”

Section: Introductionmentioning

confidence: 99%

Effect of aluminum nanoparticles on the linear and nonlinear optical properties of PVA

Naseri

Dorranian

2016

Opt Quant Electron

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Linear and nonlinear optical properties of Polyvinyl Alcohol thin film doped with aluminum nanoparticles have been investigated experimentally. Aluminum nanoparticles were produced using pulsed laser ablation method. The fundamental wavelength of Nd-YAG laser at 7 ns pulse width was employed to produce aluminum nanoparticles in water at different sizes and concentrations. TEM images were used to study the nanoparticles after ablation. UV-Vis-NIR spectroscopy data were used to extract the real and imaginary parts of refractive index and dielectric functions of films and z-scan technique was used to measure the nonlinear refractive index and absorption coefficient of films. Results show that in comparison with particle size, the concentration of doped nanoparticles is more effective on the optical properties of polymers thin films. Band gap energy of polymer films was decreased with decreasing the size and increasing the concentration of nanoparticles while their refractive index was decreased.

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Differential interferometric technique for the measurement of the nonlinear index of refraction of ruby and GdAlO_3:Cr^+3

Cited by 48 publications

References 9 publications

Optically pump-induced athermal and nonresonant refractive index changes in the reference Cr-doped laser materials: Cr:GSGG and ruby

Optically pump-induced athermal and nonresonant refractive index changes in the reference Cr-doped laser materials: Cr:GSGG and ruby

Experimental and theoretical investigation of a nonlinear lensing effect observed in a Cr:LiSAF laser

Effect of aluminum nanoparticles on the linear and nonlinear optical properties of PVA

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