Influence of solvent contribution on nonlinearities of near infra-red absorbing croconate and squaraine dyes with ultrafast laser excitation (original) (raw)
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Ultrafast third order nonlinearities of organic solvents
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The third order nonlinear optical parameters of a variety of organic solvents are determined under picosecond and femtosecond laser irradiation. Z-scan measurements have been carried out at 35 ps, 532 nm and at 40 fs, 800 nm, while Optical Kerr Effect studies were performed at 35 ps, 532 nm. The target of the present work is to provide a reference of the nonlinear optical response of various widely used organic solvents under the same experimental conditions and render feasible the direct comparison between their nonlinearities.
Photonics: Design, Technology, and Packaging III, 2007
There is much interest in nonlinear absorbing chromophores for applications in photonics, nanophotonics and biophotonics. We have performed studies of dispersion of the nonlinear absorption cross sections and the refractive nonlinearities of organic and organometallic nonlinear chromophores using the technique of Z-scan, with a tunable amplified femtosecond laser system. Z-scan is less sensitive than the popular technique of two-photon induced fluorescence but has advantages of being suitable for non-fluorescent substances and providing information on both absorptive and refractive nonlinearities. We have analysed the experimental results in terms of simple models and using the Kramers-Kronig transformation as shown in this paper for Coumarine 307 and an organometallic dendrimer. The dispersion curves are often dominated by two-photon resonances but inclusion of other nonlinear mechanisms seems to be necessary for better understanding of their features.
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The interaction between a two-level molecular system and a high intensity electric field under the influence of a solvent was analyzed through the OSBE. To solve these equations, the average of the coherence was performed, using a generalized Lorentzian approximation for the Voigt's function as a probability distribution. Applying the convolution theorem, we were able to find an analytical expression for the coherence, from which we calculate optical properties, such as the absorption coefficient, refractive index and emitted signal intensity. In this contribution, we show numerical results for these properties, calculated for a standard model of organic colorants, Green Malaquite.
Nonlinear Optical Properties of Water-Soluble Polymeric Dyes with Biological Applications
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The nonlinear optical properties of two water-soluble polymeric dyes, poly(R-478) (an anionic anthraquinone dye) and poly(S-119) (an anionic azo dye), are investigated utilizing nanosecond and femtosecond optical techniques such as z-scan, nonlinear transmission, and time-resolved luminescence. Poly(R-478) showed large nonlinear refraction when studied with femtosecond laser pulses at 800 nm, with a value for the intensity-dependent refractive index (n I) of 1.26 × 10-4 cm 2 /GW. The thin film result at 1064 nm indicated a large nonlinear absorption in both polymeric dyes. The origin of the large fast optical nonlinearities in the polymeric system S-119 was investigated by probing the different functional groups of the polymer. The chromophore group (Sunset Yellow) of the S-119 polymer showed a smaller nonlinear response when compared to the polymer result. Significant differences in the electronic dynamics between the parent poly(S-119) and the chromophore Sunset Yellow were observed by time-resolved luminescence spectroscopy. The applications of the NLO effects in these polymers are demonstrated for laser ablation of A549 lung carcinoma cells.
Single-beam Z-scan measurement of the third-order optical nonlinearities of triarylmethane dyes
Laser Physics, 2008
Solid-state dye-doped polymers are an attractive alternative to the conventional liquid-dye solutions. The search for new materials which have potential application in optoelectronic devices has lead us to probe the organic dyes. The solid state being a better medium when compared to a liquid medium has lead to the incorporation of dyes in the polymer matrix. The study of nonlinear characteristics of dyes in polymeric media is essential for developing such potential application devices. In this paper, the third-order nonlinear optical properties of three dyes from the Triarylmethane family were measured in 1-Butanol and in dye-doped polymer films by the Z-scan technique using a cw diode-pumped Nd:YAG laser at 532 nm. The Z-scan technique has also been used to present the observation of a nonlinear refractive index resulting from the photochromism of one of the dyes. These materials exhibit a large negative optical nonlinearity resulting due to the thermal effect. The relative contributions from the nonlinear absorption (NLA) and nonlinear refraction (NLR) are dependent on the chemical structure and linear absorption of the dyes. The dyes exhibited a nonlinear refractive coefficient n 2 , a nonlinear absorption coefficient β , and susceptibility χ (3) on the order of 10 -8 cm 2 /W, 10 -4 cm/W, and 10 − 6 esu, respectively, in both liquid and solid media. The results show that these dyes have potential applications in nonlinear optics.
Peer J Physical Chemistry, 2022
Measurements of nonlinear optical (NLO) properties of different binary mixtures having carbon disulfide (CS 2) as the common component, namely CS 2-acetone, CS 2cyclopentanone, CS 2-toluene, and CS 2-carbon tetrachloride (CCl 4), are carried out by using the z-scan technique. Open-aperture z-scan (OAZS) and close-aperture z-scan (CAZS) experiments are performed to determine the nonlinear absorption coefficient (β) and nonlinear refractive index (n 2) of all binary liquid mixtures at various compositions of the components by employing a pulsed, high repetition rate (HRR) femtosecond laser. Also, we were able to use the flowing liquid to measure NLO properties in the CS 2-acetone binary mixture to remove the cumulative thermal effects produced due to the pulsed HRR laser light. Nonlinear refractive index (n 2) values are found to be influenced by the weak dipole-induced dipole intermolecular interactions between the nonpolar CS 2 and polar acetone as well as cyclopentanone of the respective binary mixtures. On the contrary n 2 values are not found to be affected by the intermolecular interactions in CS 2-toluene and CS 2-CCl 4 binary mixtures. In comparison, the nonlinear absorption coefficient (β) values are not found to be affected by the same in all different sets of binary mixtures.
Characterization of the ultrafast nonlinear response of new organic compounds
Organic Photonic Materials and Devices XXII, 2020
Here, we present our development of several experimental methods, which, when applied together, can provide a thorough characterization of the nonlinear refraction and absorption properties of materials. We focus mainly on time-resolved methods for studying both transient absorption and refraction that reveal molecular dynamics including excited-state absorption, singlet-triplet transfer, instantaneous electronic nonlinear refraction, and molecular reorientation. In particular, we will describe our recent studies of new materials including organometallic compounds and organic solvents such as Tetrachloroethylene (C2Cl4).
Z-scan studies and optical limiting of nanosecond laser pulses in neutral red dye
Optics and Laser Technology, 2008
The nonlinear optical absorption, refraction and optical limiting behaviour of an organic dye, neutral red, were investigated under excitation with nanosecond laser pulses at 532 nm. The nonlinear optical responses of the material were studied both in solution and solid film, made in methanol and polyvinyl alcohol, respectively, using single-beam Z-scan technique. The open aperture Z-scans of the solution samples displayed a switch over from saturable absorption to enhanced absorption with increase in input intensity. Theoretical fit to the experimental data indicated that the dominant mechanism of nonlinear absorption is two-photon absorption. The closed aperture Z-scans of both the samples denoted positive nonlinearity, which was three orders larger in magnitude in solid film, compared with that in solution. The results of optical limiting experiments revealed that neutral red exhibited strong optical limiting of nanosecond laser pulses with a threshold lower than that of C 60 in toluene. r