Third-order nonlinear optical properties of bismuth-borate glasses measured by conventional and thermally managed eclipse Z scan

Third-order nonlinearity one order of magnitude larger than silica is measured in bismuth-borate glasses presenting a fast response (<200 fs). The results for the sign and magnitude of the nonlinearity were obtained using a combination of the eclipse Z scan with thermal nonlinearity managed Z scan, whereas the Kerr shutter technique was employed to obtain the electronic time response of the nonlinearity, all performed with 76 MHz repetition rate 150 fs pulses at 800 nm. Conventional Z scans in the picosecond regime at 532 and 1064 nm were also independently performed, yielding the values of the third-order nonlinear susceptibilities at those wavelengths. The results obtained for the femtosecond response, enhanced third-order nonlinearity of this glass (with respect to silica), place this glass system as an important tool in the development of photonics devices. Electro-optical modulators, optical switches, and frequency converters are some of the applications using second-order nonlinear properties of the Bi-glass based on the rectification model

Three-dimensional spatial solitons in CS2

International audienc

Near-infrared Kerr nonlinearity of Pb(PO3)2–WO3 glasses

We report measurements of the nonlinear refractive index, n 2 , and the nonlinear absorption coefficient, α 2 , of Pb ( PO 3 ) 2 – WO 3 glasses. The measurements were performed using 100 fs (17 ps) laser pulses at 800 nm (1064 nm). Positive values of n 2 ∼ 10 − 19 m 2 / W and negligible α 2 were measured. The results show that the nonlinearity is faster than 100 fs and it is observed an increase of n 2 with the increasing of the WO 3 amount in the samples. The Boling, Glass, and Owyoung model, based on the semiclassical harmonic oscillator model, was used to predict the values of n 2 , with basis on the values of the linear refractive index of the samples

Near‐infrared dissipative three‐dimensional spatial solitons in CS2

International audienc

Robust Two-Dimensional Spatial Solitons in Liquid Carbon Disulfide

The excitation of near-infrared ð2 þ 1ÞD solitons in liquid carbon disulfide is demonstrated due to the simultaneous contribution of the third- and fifth-order susceptibilities. Solitons propagating free from diffraction for more than 10 Rayleigh lengths although damped, were observed to support the proposed soliton behavior. Numerical calculations using a nonlinear Schro ̈dinger-type equation were also performed

Efeito da adição de uréia e sulfato de amônio sobre o pH e nitrificação em um solo ácido

The variation of pH and the production of nitrate were studied in a Dark Red Latosol, Guamium séries, in function of the addition of 200 and 400 ppm of N, as urea and ammonium sulphate in the presence and absence of Ca(0H)2, for a period of 30 days. The results obtained showed that the pH decreased with ammonium sulphate and increased with urea. The variations were observed even in the presence of Ca(0H)2. The production of nitrate increased with pH considering the same level and source of nitrogen.A variação do pH e a produção de nitrato foram estudados em um Latossolo Vermelho Escuro, Série Guamium, em função da adição de 200 e 400 ppm de N nas formas de uréia e sulfato de amônio, em presença e ausência de Ca(OH)2 por um período de 30 dias. Os resultados obtidos mostraram que o pH decresceu com o sulfato de amônio e aumentou com a uréia. As variações foram observadas mesmo empresença de Ca(0H)2. A produção de nitrato aumentou com o pH, considerando o mesmo nível e fonte de nitrogênio. Não foi observado no conjunto uma relação entre pH e produção de nitrato

Picosecond third-order nonlinearity of lead-oxide glasses in the infrared

Heavy metal-oxide glasses containing lead and bismuth were prepared, and their picosecond third-order nonlinear (NL) optical characteristics were investigated. NL refractive indices of ≈ 10−18 m2/W at 1064 nm were measured. Negligible NL absorption was verified and, as a consequence, the samples present a good factor-of-merit for photonic applications

Near-infrared nonlinearity of a multicomponent tellurium oxide glass at 800 and 1,064 nm

We report on the nonlinear (NL) optical properties of glassy TeO2–GeO2–K2O–Bi2O3 at λ = 800 nm and λ = 1,064 nm. Using the Kerr gate technique with a laser delivering 150 fs pulses at 800 nm, we demonstrated the fast NL response of the samples. The modulus of the NL refractive index, n 2, at 800 nm was ~10−15 cm2/W. The Z-scan technique was used to determine n 2 ≈ +10−15 cm2/W, at 1,064 nm with pulses of 17 ps. The two-photon absorption coefficient, α 2, was smaller than the minimum that we can measure (<0.003 cm/GW). The figure of merit n 2/α 2 λ was calculated and indicates that this glass composition has large potential to be used for all-optical switching

Effect of sequential medium on in vitro culture of goat ovarian cortical tissue

A sequential medium was evaluated on the survival, activation and growth rates of caprine preantral follicles submitted to a long-term culture period, aiming to establish an ideal in vitro culture system. Ovarian fragments were cultured for 16 days in α-MEM+ alone or supplemented with hormones (GH and/or FSH) added sequentially on different days of culture. Ovarian fragments were cultured in the first (days 0–8) and second (days 8–16) halves of the culture period, generating 10 treatments: α-MEM+/α-MEM+, FSH/FSH, FSH/GH, FSH/FSH + GH, GH/GH, GH/FSH, GH/FSH + GH, FSH + GH/FSH + GH, FSH + GH/FSH and FSH + GH/GH. Follicle morphology, viability and ultrastructure were analyzed. After day 1 of culture, FSH treatments maintained the percentage of normal follicles similar to the fresh control. At day 16 of culture, the treatment FSH/GH showed the highest (P < 0.05) percentage of normal follicles. The ultrastructure of follicles was preserved in the fresh control and FSH/GH treatment. Follicles cultured with FSH/GH had a higher (P < 0.05) viability than α-MEM+; however the viability was lower (P < 0.05) when compared to the fresh control. The FSH/GH treatment showed the highest (P < 0.05) percentage of follicular activation and secondary follicle formation and produced the largest (P < 0.05) mean follicular diameter after 16 days of culture. In conclusion, a sequential medium supplemented with FSH followed by GH during a long-term culture maintains the survival, viability and ultrastructure of goat preantral follicles, and promotes activation and secondary follicles