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Experimental methods, mathematical formulations, complementary results, including figures of measured results and tables of the calculated and reported NLO coefficients.

Metal-organic framework (MOF) glasses are a newly discovered family of melt-quenched glasses. However, so far it is not known whether these glasses exhibit photonic functionalities. Here, we show the discovery of the luminescent behavior of a MOF glass, i.e., the cobalt doped zeolitic imidazolate frameworks-62 (ZIF-62) glass (Zn1-x Cox (Im)1.9 (bIm)0.1, x = 0, 0.1 and 0.5), which was obtained by melt-quenching its corresponding ZIF-62 crystal. The synthesized crystal was precipitated in the form of spherical nano/micro-crystalline structure, which collapses structurally to form laminated glass with ultrahigh glass forming ability and the same short range molecular structure of the parent crystalline MOF. We observed the super-broadband mid-infrared (Mid-IR) luminescence (in the wavelength range of 1.5 µm – 4.8 µm) both in the crystalline and amorphous phases. The observed Mid-IR emission originates from d-d transition of Co2+ ions that is protected by the strong Co-N coordination. The discovery of the luminescent glasses may pave the way towards new photonic applications of bulk MOF glasses, such as Mid-IR lasers.

Dynamical materials that capable of responding to optical stimuli have always been pursued for designing novel photonic devices and functionalities, of which the response speed and amplitude as well as integration adaptability and energy effectiveness are especially critical. Here we show ultrafast pulse generation by exploiting the ultrafast and sensitive nonlinear dynamical processes in tunably solution-processed colloidal epsilon-near-zero (ENZ) transparent conducting oxide (TCO) nanocrystals (NCs), of which the potential respond response speed is >2 THz and modulation depth is ~23% pumped at ~0.7 mJ/cm2, benefiting from the highly confined geometry in addition to the ENZ enhancement effect. These ENZ NCs may offer a scalable and printable material solution for dynamic photonic and optoelectronic devices.

This paper studies the photosensitive effect of cerium oxide on the precipitation of Ag nanoparticles after femtosecond laser irradiating into silicate glass and successive annealing. Spectroscopy analysis and diffraction efficiency measurements show that the introduction of cerium oxide may increase the concentration of Ag atoms in the femtosecond laser-irradiated regions resulting from the photoreduction reaction Ce3+ + Ag+ → Ce4+ + Ag0 via multiphoton excitation. These results promote the aggregation of Ag nanoparticles during the annealing process. It is also found that different concentrations of cerium oxide may influence the Ag nanoparticle precipitation in the corresponding glass.

Near-infrared luminescence is observed from bismuth-doped GeS2—Ga2S3 chalcogenide glasses excited by an 808 nm laser diode. The emission peak with a maximum at about 1260 nm is observed in 80GeS2-20Ga2S3:0.5Bi glass and it shifts toward the long wavelength with the addition of Bi gradually. The full width of half maximum (FWHM) is about 200 nm. The broadband infrared luminescence of Bi-doped GeS2-Ga2S3 chalcogenide glasses may be predominantly originated from the low valence state of Bi, such as Bi+. Raman scattering is also conducted to clarify the structure of glasses. These Bi-doped GeS2-Ga2S3 chalcogenide glasses can be applied potentially in novel broadband optical fibre amplifiers and broadly tunable laser in optical communication system.

The ferroelectric crystal Ba2TiSi2O8 with high second-order optical nonlinearity is precipitated in Sm3+-doped BaO-TiO2-SiO2 glass by a focused 800nm, 250kHz and 150 fs femtosecond laser irradiation. No apparent blue and red emissions are observed at the beginning, while strong blue emission due to second harmonic generation and red emission due to the f-f transitions of Sm3+ are observed near the focal point of the laser beam after irradiation for 25s. Micro-Raman spectra confirm that Ba2TiSi2O8 crystalline dots and lines are formed after laser irradiation. The mechanism of the phenomenon is discussed.

Multiple refocusing of a tightly focused femtosecond laser due to the dynamic transformation between self-focusing and self-defocusing is employed to provide a novel method to produce quasi-periodic voids in glass. It is found that the diameter or the interval of the periodic voids increases with the increasing pulse energy of the laser. The detailed course for producing periodic voids is discussed by analysing the damaged track induced by the tightly focused femtosecond laser pulses. It is suggested that this periodic structure has potential applications in fabrication of three-dimensional optical devices.

We report on structural change in an Au3+-doped BK7 glass irradiated by an infrared femtosecond laser at 800 nm. A grating structure is inscribed in the glass sample. The glass sample is then annealed at various temperatures. Structural change of the grating is observed by an optical microscope. Absorption spectra indicate that colour centres are induced after the laser irradiation, and they decrease with increasing annealing temperature. Au nanoparticles are precipitated at high temperatures (≥600°C). The mechanisms of the phenomena are discussed.

We report transparent Ni2+-doped ZnO-Al2O3-SiO2 system glass-ceramics with broadband infrared luminescence. After heat-treatment, ZnAl2O4 crystallite was precipitated in the glasses, and its average size increased with increasing heat-treatment temperature. No infrared emission was detected in the as-prepared glass samples, while broadband infrared luminescence centered at 1310 nm with full width at half maximum (FWHM) of about 300 nm was observed from the glass-ceramics. The peak position of the infrared luminescence showed a blue-shift with increasing heat-treatment temperature, but a red-shift with an increase in NiO concentration. The mechanisms of the observed phenomena were discussed. These glass-ceramics are promising as materials for super broadband optical amplifier and tunable laser. (c) 2006 Elsevier Ltd. All rights reserved.

We report on an optical interference method to fabricate arrayed holes on metal nickel foil and aluminum film deposited on glass substrate by means of five-beam interference of femtosecond laser pulses. Optical microscope and scanning electron microscope observations revealed that arrayed holes of micrometre-order were fabricated on both metal foil and metal film. The present technique allows one-step, large-area, micrometric processing of metal materials for potential industrial applications.

The formation of infrared femtosecond laser induced colour centres was observed in Tb3+-doped and Tb3+/Ce3+-codoped heavy germanate glasses. A rectangular scan was made by focusing the laser beam inside the glass samples. A three-dimensional yellowish block was created from the path and it corresponded to the appearance of broad absorption bands in the absorption spectra. The irradiation induced absorption coefficient μ(λ) was used to characterize the distribution of radiation induced colour centres in the samples, whose peak was located at 380 nm and extended to the longer wavelength. Ce3+ ions were found not only to inhibit the formation of colour centres, but also to enhance the recovery. \pacs{61.80.Ba, 73.61.Jc, 74.25.Gz, 76.30.Kg, 73.43.Fj

The thresholds of laser-induced darkening in different optical glasses irradiated by a 800 nm, 120 fs, 1 kHz Ti:sapphire laser are reported for the first time. Absorption spectra of the glasses before and after irradiation were measured. The absorption in visible region of the irradiated glasses increased greatly after irradiation and then decreased slightly along with time. The mechanism of the laser-induced darkening was demonstrated based on the ESR measurement and excimer laser irradiation results.

Physical structures and combustion properties of super fine pulverized coal particles of eight Chinese coals, Heshan subbituminous coals and Jincheng lean coals from two areas of China, have been investigated using accelerated surface area and porosimetry, thermobalance (TGA), and Fourier transform infrared spectrometer. Results showed that the particle specific surface area and pore volume increased greatly when the coal particle size was reduced. The higher the carbon content on a dry ash-free basis is, the larger the particle specific surface area and pore volume are. When the coal particle size decreases, the combustion process can be largely improved, ignition temperature is reduced, and SO 2 emission from coal combustion is also lower.

PbS-doped glasses are prepared. Absorption and luminescence spectra show that both the absorption and infrared emission can be tuned widely by thermal treatment conditions. Optical amplification at 1300nm is observed, and amplified spontaneous emission (ASE) spectrum is also measured to confirm the optical gain from PbS quantum dots.

We report on cooperative quantum cutting in Tb3+-Yb3+ codoped glass ceramics. Precipitation of BaF2 nano-crystals is confirmed by XRD and HRTEM analysis. Near-infrared emission due to transition of Yb3+ ions under 485 nm excitation indicates cooperative energy transfer from Tb3+ to Yb3+. The quantum efficiency of this process reaches 145%. The realization of quantum cutting in glass ceramics may have promising applications in solar cells.

The femtosecond laser induced void array inside Al2O3 crystals was discussed. The void array was formed spontaneously under the irradiation of a single beam of infrared femtosecond laser which was focused at a fixed point inside the Al2O3 crystal sample. It was found that the regular voids only could be fabricated near the sample surface, which was different from the situation in CaF2 single crystal reported before. The possible mechanism of the phenomena was also discussed.

Transparent Ni2+-doped magnesium aluminosilicate glass ceramics are prepared. The formation of petalite-type crystallites in the glass ceramics is confirmed by x-ray diffraction. Broadband infrared luminescence centred at around 1235 nm with full width at half maximum (FWHM) of about 300 nm is observed from the Ni2+-doped glass ceramics. The observed infrared emission could be attributed to the 3T2(F)→3A2(F) transition of octahedral Ni2+ ions in petalite-type crystallites. The product of the fluorescence lifetime and the stimulated emission cross sections is 1.2×10−24 cm2s.

The fabrication of one kind of large core area Nd 3+ doped silicate glass photonic crystal fiber, and demonstration of the fiber's waveguidence properties were reported. This fiber owns a random air hole distribution in the cladding. The measured minimum loss of this kind of fiber is 10 dB· m −1 at 660 nm. These fibers can sustain only a single mode at least over wavelength ranging from 660 nm to 980 nm.

Broadband near-infrared emission from transparent Ni2+-doped sodium aluminosilicate glass-ceramics is observed. The broad emission is centred at 1290 nm and covers the whole telecommunication wavelength region (1100–1700 nm) with full width at half maximum of about 340 nm. The observed infrared emission could be attributed to the 3T2(F)→3A2(F) transition of octahedral Ni2+ ions that occupy high-field sites in nanocrystals. The product of the lifetime and the stimulated emission cross section is 2.15×10−24 cm2s. It is suggested that Ni2+-doped sodium aluminosilicate glass ceramics have potential applications in tunable broadband light sources and broadband amplifiers.

Extended X-ray absorption fine structure (EXAFS) near the Ge K-edge in glasses of the GeO 2 TeO 2 system was measured. The results were analyzed with both the GeO 4 GeO 6 two-shell model and the GeO 4 single-shell model. Since the two-shell model gave a better fit of the measured EXAFS it was concluded that the germanate anomaly should be interpreted by the convention, namely, the formation of GeO 6 units. The fraction of the GeO 6 units decreased from 0.46 to 0.266 as the GeO 2 content increased from 12 to 68 mol%.

Upconversion nanoparticles (UCNPs) have made a significant and valuable contribution to photophysics and biomedicine, due to their specific spectroscopic characteristics. However, the ensemble spectroscopy of UCNPs is limited for the electronic behavior in average effect, which ignores the fact that the nanoparticles are heterogeneous. Towards the research focus on heterogeneous intrinsic structure, unique photophysical phenomena, and advanced applications, the optical characterization of single UCNPs are promoted to a frontier breakthrough of UCNPs community. Electronic behavior detection aimed at a single nanoparticle displays signals from the micro-structure of nanoparticles, while single nanoparticle spectroscopy offers clear insight into the interplay between intrinsic and extrinsic influences without noise, and subsequently gives instructions for the high quality preparation of UCNPs. Single nanoparticle optical characterization possesses a powerful capacity to explore the crystalline structure anisotropy related optical differences, or some unexpected unique optical phenomena at sub-micron and even nano-scale. In this review, the importance of single UCNPs characterization and single particle detection methods are overviewed, in which the considerable emphasis is placed on the specific spectroscopic study of single UCNPs Showing fantastic photophysical phenomena beyond ensemble measurement. Finally, this review identifies 1024 无 机 材 料 学 报 第 31卷 promising opportunities in which single UCNPs characterization technique can accelerate on-going research with a remarkable depth and breadth, facilitate discovery of upconversion nanoparticles that overcome fundamental limitations of current ensemble level.

We report the space-selective formation of colour centres and refractive index change in LiF crystals at room temperature by an 800 nm Ti:sapphire femtosecond laser irradiation. Optical absorption and photoluminescence spectra have been measured for the crystal before and after the laser irradiation. The absorption spectra indicate F and F3+ colour centres are induced in LiF after the laser irradiation. When the temperature of heat treatment reaches 300°C, the absorption peak disappears, indicating that the induced colour centres are bleached. The induced refractive index change is also evaluated. A mechanism for the formation of colour centres and refractive index change is proposed.

The 720 and 780cm-1 components of the deconvoluted Raman spectra of glasses in the systems RnO-TeO2 (R=Li, Na, K, Ba, Zn) were attributed to TeO3 groups and the 665cm-1 band was to TeO4 groups. The theoretical values of the molar ratio TeO3/TeO4 derived from an assumed vitrification reaction were compared with the ratio derived from the intensity ratios of the Raman bands, I(720)/I(665) and I(780)/I(665). It was indicated that [O2/2Te=O] and [O1/2Te(=O)-O]- units were induced by the addition of network modifying oxides in the composition range of lower atomic ratio O/Te. It was proposed that the decrease in the rate of increase of the ratio TeO3/TeO4 in the range of larger O/Te was due to the equilibrium TeO4/2↔[O2/2Te=O] favoring the former unit.