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A strong coherent effect was observed in the monochromatic optical Kerr effect (OKE) experiment of a Bi2O3-B2O3-SiO2 oxide glass (BI glass). To eliminate the influence of the coherent effect, we proposed a simple femtosecond two-color OKE measurement method with wavelength tunability using a supercontinuum. In the two-color OKE measurement the third order nonlinear susceptibility of the BI glass was measured to be 1.64 × 10-13 electrostatic units (esu), in which the influence of the coherent effect was eliminated. The result is smaller than that obtained in a previous monochromatic OKE experiment. In addition, we discuss the discrepancies between the result obtained in this paper and those reported in other studies. [ABSTRACT FROM AUTHOR]

Abstract: Fabrication of three-dimensional microfluidic channels in glasses by water-assisted ablation with femtosecond laser pulses was investigated. The experimental results showed that formation of the photoinduced microchannels by femtosecond pulses depended on the incident laser power and the scanning speed. For the same scanning speed, the shape of cross-section of channels changed from ellipse to circle with increasing the laser power. Under the optimum condition of laser processing, we fabricated two layers of microfluidic channels with diameter of about 8μm inside glass. The distance between two layers of microchannels was about 20μm. [Copyright &y& Elsevier]

Abstract: The ultrafast nonlinear optical properties of Bi2O3–B2O3–SiO2 oxide glass were investigated using a femtosecond optical Kerr shutter (OKS) at wavelength of 800nm. The nonlinear response time of this Bi2O3-doped glass was measured to be <90fs. The nonlinear refractive-index n 2 was estimated to be 1.6×10−14 cm2/W. Measurements for the dependence of Kerr signals on the polarization angle between the pump and probe beams showed that the Kerr signals induced by 30-fs pulse laser arose mainly from the photoinduced birefringence effect. [Copyright &y& Elsevier]

Second-harmonic generation (SHG) has been observed in optically poled Y52 filter glass. Both encoded second-harmonic intensity and relaxation time for decay of second-harmonic intensity increase with an increase in poling time and power of laser at 532 nm used for optical poling. It is thought that the longer poling time and higher laser power for poling increase the number of positive holes and electrons, a periodic arrangement of which brings about automatically phase-matched SHG, leading to large second-harmonic intensity. The increase in relaxation time caused by optical poling for longer time and with higher laser power is presumably ascribed to thermal effect which can give rise to formation of positive holes and electrons at deeper energy levels. [Copyright &y& Elsevier]

Abstract: We investigated the ultrafast optical Kerr effect of the fluorotellurite glass (Ft glass), the nonlinear response time of which was measured to be less than 230fs, while the nonlinear refractive index was estimated to be 9.62×10−16 cm2/W. Using optical Kerr gate (OKG) technique with Ft glass as Kerr medium, we obtained narrow-bandwidth and symmetric gated spectra from a supercontinuum (SC) generated by a femtosecond laser. Experimental results indicated that Ft glass was a good candidate for an OKG medium due to its fast response time, large nonlinearity, and high transparency. [Copyright &y& Elsevier]

Highlights: [•] Fluorotellurite glass is a new mid-IR fiber laser material. [•] Physical and chemical dehydration method removed OH group from bulk mid-IR glass. [•] Emission intensity at 2.71μm was enhanced with the incorporation of Pr3+ ion. [•] The introduction of Pr3+ ion improved fluorescence lifetime from 1.07 to 1.55ms. [•] Er/Pr-TZNF60 glass is a deal material to develop mid-IR fiber lasers at 2.7μm. [ABSTRACT FROM AUTHOR]

We report the precipitation and control of metal nanoparticles inside transparent glasses. An Ag[sup +]-doped silicate glass sample was first irradiated by using an 800 nm femtosecond laser at room temperature and then annealed at 550 °C. The area near the focal point of the laser beam became gray after laser irradiation and yellow after further annealing at 550 °C for 10 min. Absorption and electron spin resonance spectra of the glass sample showed that a portion of silver ions near the focused part of the laser beam inside the glass were reduced to silver atoms after the laser irradiation. These silver atoms aggregated to form nanoparticles after further annealing at temperatures above 500 °C. A mechanism is suggested that consists of multiphoton reduction, which is induced by the fundamental light of the laser beam and supercontinuum white light, and diffusion of silver atoms driven by heat energy to form nanoparticles. The observed phenomenon may have promising applications for the fabrication of three-dimensional multicolored images inside a transparent material and for integrative micro-optical switches. [ABSTRACT FROM AUTHOR]

We report the observation of space-selective oxidation of Mn[sup 2+] to Mn[sup 3+] in a transparent and colorless Mn and Fe ions codoped silicate glass at room temperature by using an 800-nm-femtosecond laser. Difference absorption spectrum of the glass after and before the irradiation of the focused infrared femtosecond pulsed laser showed that a portion of Mn[sup 2+] ions near the focused part of the laser beam inside the glass were oxidized to Mn[sup 3+] ions after the laser irradiation. Mn[sup 3+] ions were stable at the temperatures below 300 °C. It is suggested that Mn[sup 2+] ions act as hole trapping centers while Fe[sup 3+] ions as well as active sites in the glass matrix act as electron trapping centers. A promising application was demonstrated for the fabrication of three-dimensional colored image inside a transparent material. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]