This paper gives the overview of developing optical glasses in last century and points out the important role still paid in modern optical and optoelectronic engineering. The emphases in this paper have been laid on photonic glasses including their different functional roles in comparison with optical glasses, importance in exploration of new photonic devices, as well as their new directions of development.

No abstract available.

As₂S₃ glass shows prominent optical and structural changes when illuminated with photons of sub-bandgap energy. The changes can be employed to produce optical devices such as Bragg filters and microlenses. The phenomena are reviewed, and the mechanisms are discussed.

No abstract available.

Oxide glasses have been used since long time to host a number of active compounds, first of all rare-earth (RE) ions, for lasing. Recently, the advantages offered by guided-wave format, namely the small size, the high pump power density, and the larger flexibility in design and fabrication, led to the development of fiber lasers and amplifiers based on Er³⁺-doped glasses. Currently, a growing activity is aimed at achieving large optical gain in Er³⁺-doped planar waveguides, having in mind the single-chip realization of integrated optical amplifiers and lasers. The aim of the present paper is to provide a quick overview of this area and to briefly discuss possible future developments.

Since the success of the Er-doped fiber amplifier, the rare earth doped glasses have attracted much attention as a candidate of optical amplifiers for broad-band wavelength-division-multiplexed (WDM) telecommunication as a result of growing demand for transmission capacity. In order to improve the amplifier performance, the development of novel host materials is important. To broaden the emission spectra of doped rare earth ions in glasses, it is important to understand the relationship between the local ligand field and various optical properties due to related 4f-transitions, such as the radiative transition probability, the nonradiative decay rate, which dominate the spectral linewidth and quantum efficiency of amplification transitions. For the Er³⁺: 1.55 μm transition, the role of Judd-Ofelt Ω₆ parameters is presented on the emission bandwidth, which is correlated to the Er-ligand bond covalency in glasses. The Tm³⁺: 1.46 μm transition shows quantum efficiency over 90%, high enough for the S-band application, in heavy metal oxide glasses with moderate phonon energy, in which wider emission spectra are obtained than in fluorides. Novel glass materials have potential to vary the radiative cross section, quantum efficiency, and gain bandwidth, which are important for amplifiers in the future WDM system.

Several nano liters of tellurite glass melt (xTeO₂ - (100 - x)ZnO, x = 80,90,100 in mol%) were inserted and quenched between tow ends of silica glass optical fibers to form a new optical coupling structure, whose length was several hundred microns. No visible precipitates were found even in the quenched melt of 100% TeO₂. On the basis of reflection and insertion loss measurements and a bending test, it is proved that there’s no micro crystals in the quenched melt segment which cause light scattering and/or stress concentration. Few tens nano liters of the melt were also inserted into a silica glass capillary tube with the tube diameter of 125μm, in order to examine their tolerance to the residual stress induced on cooling due to the large gap in thermal expansion coefficient between the two glasses. Neither fracture nor bubbles were observed in the quenched melt inside if its length is less than 2mm. This implies that tellurite melt can be introduced into voids of sub-mm in size to integrate hybrid lightwave circuits.

In the field of LANs, transmission systems based on a multimode silica fiber network is heading towards capacities of Gb/s. We have proposed a low-loss, high-bandwidth and large-core graded-index plastic optical fiber (GI POF) in data-com. area. We sill show that GI POF enables to virtually eliminate the “modal noise” problem cased by the medium-core silica fibers. Therefore, stable high-speed data transmission is realized by GI POF rather than silica fibers. Furthermore, advent of perfluorinated (PF) polymer based GI POF network can support higher transmission than silica fibers network because of the small material dispersion of PF polymer compared with silica. In addition, we proposed a “highly scattering optical transmission (HSOT) polymer” and applied it to a light guide plate of a liquid crystal display (LCD) backlight. The advanced HSOT polymer backlight that was proposed using the HSOT designing simulation program demonstrated approximately three times higher luminance than the conventional flat-type HSOT backlight of 14.1-inch diagonal because of the microscopic prism structures at the bottom of the advanced HSOT light guide plate. The HSOT polymer containing the optimized heterogeneous structures produced homogeneous scattered light with forward directivity and sufficient color uniformity.

The heavy metal oxide (HMO) glasses in the ternary Bi₂O₃-WO₃-TeO₂ system were prepared to investigate the Er³⁺ amplification properties. The present HMO glasses showed larger and broader Er³⁺ emission spectra as compared with the conventional silica-based glasses. Dominant factors on the emission intensity and bandwidth were explored on the basis of theories. The emission intensity was successfully explained by the theoretical radiative decay rate, and it was also confirmed that the refractive index was predominant on the emission intensity. A Judd-Ofelt Ω₆ parameter was also examined, and its influence on the bandwidth was not recognized. Other factors, such as O1s binding energy and structural variation around Er³⁺ ions, were estimated, and their effects on the bandwidth were however not clarified. The unique chemical bonding character in the HMO glasses might be responsible for the spectral broadening.

The possibility of developing 1.6μm band optical amplifiers was investigated using the emission from the Ho³⁺-doped cholcogenide glasses. Selenide and sulfide glasses with a low vibrational phonon energy were used as host materials. The maximum Ho³⁺ concentration in the glasses was 0.08mol% due to the cross relaxation process. Tb³⁺ co-doping reduced the lifetimes of the Ho³⁺:⁵I₇ level and thereby, provided opportunities for the population inversion.

New phenomena of anisotropic light scattering, anisotropic Cherenkov third-harmonic generation, photoinduced birefringence and anisotropic reflection from femtosecond direct-write structures are reviewed. The phenomena reveal new mechanism of light-matter interaction.

Femtosecond laser is a perfect laser source for materials processing when high accuracy and small structure size are required. Due to the ultra short interaction time and the high peak power, the process is generally characterized by the absence of heat diffusion and, consequently molten layers. Various induced structures have been observed in glasses after the femtosecond laser irradiation. Here, we report on space-selective valence state manipulation of active ions, long-lasting phosphorescence and photostimulated long-lasting phosphorescence phenomena in the femtosecond laser-irradiated glasses, and recent development of direct writing of optical waveguide in glasses with femtosecond laser pulses.

Single shot irradiation of interfered fs laser pulses allows for encoding non-erasable periodic nano-structures in almost all kinds of materials. However, strong absorption of the intense laser pulses at the material surface and the possible distortion of the pulse due to the non-linear interaction with materials make it very difficult to fabricate embedded structures inside inorganic dielectric materials. We have overcome this difficulty by using chirped pulses from Ti:sapphire fs pulse laser. The chirping stretches laser pulse width from 100 fs to 5 ps without changing the total energy, thus reducing the peak energy of the pulse. Multiple micro-gratings were encoded vertically inside silica glass at a depth of ~5 mm from the surface by using the pulse with an optimized pulse width of 500 fs. The present technique provides unique opportunity to fabricate embedded diffractive devices such as fiber gratings of pure silica fiber, optical couplers in planar waveguides and diffractive gratings in DFB lasers.

No abstract available.

Different physical processes at the surface of glass and glass-like materials, taking place under the laser irradiation with the wavelength lying in the region of fundamental absorption of them are considered. Principles of laser-based equipment for optical components fabrication are discussed. Laser smoothing and aspherisation of optical surfaces, fabrication of fiber-optical components as medical tools, scanning near-field optical microscopy (SNOM)-tips are demonstrated.

We propose and demonstrate gratings and two-dimensional (2D) photonic structure of nanometer-scale crystals/particles in glass surface created by one of the most simple way every reported. Grating structures consisting of nanocrystals have been fabricated on surface of tellurite-based glasses, with a composition of 15K2O-15Nb2O5-70TeO2 (mol%), using photoinduced nano-crystallization. A conventional phase mask technique was performed for the grating fabrication with a XeCl excimer laser operating at 308 nm. Periodic structure with 400 nm pitch constructed by lines of regularly ordered nanoparticles having a diameter up to about 100 nm was confirmed by atomic force microscopy and scanning electron microscopy. It is strongly suggest from measurement of X-ray diffraction that the photoinduced nanoparticles have a crystalline phase, and also suggested from measurement of optical frequency doubling that the periodic nanoparticle structure exhibits second harmonic generation (SHG) with an unique polarization dependence of SHG based on nano-structures of dielectric polarization. In addition, such a simple method of phase mask usage was applied to formation of 2D array, and the 2D structures of nano-particles/holes were successfully obtained by laser irradiations.

Poled TeO₂-based glass, i.e., tellurite glass, exhibits second-harmonic generation (SHG). We discuss the relationship between structural change brought about by thermal and optical poling and induced second-order nonlinearity in tellurite glasses. It is know that for thermal poling the SHG-active region caused by poling is restricted within a thin layer beneath the anode-side glass surface. The thermal poling-induced structural change such as variation of structural units and incorporation of impure species on the anode-side surface are confirmed for ZnO-TeO₂ and WO₃-TeO₂ glasses. On the other hand, for optical poling, change of valence state of vanadium is an important factor to induce SHG in vanadium-doped Nb₂O₅-TeO₂ glasses.

Three-dimensionally manipulated gold nanoparticles were precipitated in silicate glass containing gold ions by irradiation with femtosecond pulsed laser and successive heat treatment. Influence of the heat treatment conditions on the gold nanoparticles precipitation behaviors was investigated. For the tested silicate glass, the treatment temperature threshold of irradiated area for color appearance was obviously lower than that of non-irradiated area. Along with increasing the treatment temperature from such threshold, the irradiated area turned to be colorful. And finally the whole glass became multicolored corresponding to a certain high temperature. Absorption spectrum measurement indicated that, under the given irradiation condition, the sizes of Au nanoparticles were obviously affected by the heat treatment temperature.

We report on the observation of space-selective precipitation of silver nanoparticles in the Ag₂O doped silicate glass in a method of irradiation with an 800nm femtosecond laser and then heat-treatment. The irradiated portion of the glass first became gray in color after irradiation of the femtosecond laser and then turned into yellow after further heat-treatment at around 400 °C. An absorption peak at 402 nm observed in the absorption spectra of the irradiated and heat-treated glass indicates that silver nanoparticles have precipitated in the irradiated region of the glass. A possible mechanism has been suggested that the Ag⁺ ions in the region irradiated are first reduced to Ag atoms by femtosecond laser through multiphoton absorption and then accumulate to form silver nanoparticles when glass sample was heat-treated. The observed phenomenon should have potential applications in fabrication of ultrafast all-optical switch.

Laser induced darkening in two kinds of glasses, the Nd-doped silicate laser glass and type N31 Nd-doped phosphate laser glass, were studied by exposing the glass samples in 266nm nanosecond UV laser and 800nm IR femtosecond laser. UV laser and IR fs laser induced different types of color centers in silicate glass, while in phosphate glass, UV laser and fs laser generated same type of color center. Possible mechanisms of color center formation were discussed.

In recent years a considerable effort has been aimed at developing and characterizing glasses with large and fast optical nonlinearities, motivated largely by the potential application of these materials in all-optical switching devices. We will review our work in this area, with a focus on femtosecond measurements of new materials at 1.3 and 1.55 microns. These provide all possible information about the nonlinear response of the materials. Recent studies of As-S-Se, Ge-As-Se, and Ge-As-S-Se glasses reveal several materials with nonlinear refractive indices 1000 times larger than that of fused silica, as well as materials with figures of merit that are adequate for effective optical switching. These studies also provide information about the dispersion of the nonlinearities, which in turn sheds light on the mechanisms responsible for the nonlinear response.

Optical quality porous silicon (PSi) and nanoparticle crystalline-Si (c-Si) enriched SiO₂ materials were studied by absorption; luminescence; time-resolved emission measurements. Using tunable ultrafast laser as a light source, the excited state dynamics was also investigated. In a nonlinear optical (NLO) spectroscopic study the pulsed degenerate-four-wave-mixing (DFWM) technique was employed. In absorption measurement all samples show a broad and intense UV absorption with a cut-off edge at ~400 nm. In photoluminescence (PL) measurement, red emission can generally be observed in both Psi and c-Si samples. At 8 K the broadband PL of PSi is peaked at ~670 nm, with the PL lifetime in microseconds regime. The band maximum shifts toward low energy side while excitation wavelength increases. The particle size distribution was estimated using the optical transmission data according to the size- energy gap relationship. DFWM measurement reveals a long lived, slowly decaying signal which emerges from the coherent response. It indicates that the excitation was highly localized. For c-Si sample, the luminescence maximum was found at higher energy side around 590 nm, but the emission lifetime is much shortened to as ~10ns. In order to understand the nature of nanocomposite, Eu dopant was introduced into the sample. The investigation of luminescence and time-resolved emission of Eu³⁺ shows that the c-Si nanoparticles are distributed in SiO₂ matrix with an average size of the nanoparticles being around 2.2 nm. The valence band (VB) to conduction band (CB) energy gap is about 2.7 ev. By ultrashort (femtoseconds and picoseconds) laser pulse excitation the charge carriers produced in CB of c-Si nanoparticles contributes to the observed optical responses. The excited state dynamical process associated with the movement of charge carriers is characterized by an instantaneous response signal, followed by buildup of the slowly decaying signal within 500ps. The analysis of the charge creation, trapping and reactivation is discussed.

We have been developing a technique of coloration and decoloration of glasses by photo-irradiation and heat-treatment for application to easily recyclable colored glass products. The mechanisms of the photo-induced coloration of glasses used in this research are a) the photo-induced defects (color centers) formation, b) the photo-induced change in oxidation state of ions, and c) the photo-induced formation of nanoparticles in glasses. The subjects for application of these phenomena to recyclable colored-glass products are presented. The research examples for each mechanism are presented in this paper as follows: 1) the effect of the doped Fe ions on the optical density and stability of coloration due to color centers, 2) the coloration by the change in oxidation state, (formula available in paper) and 3) the reversible coloration and decoloration for an Ag single-doped glass.

The persistent spectral hole-burning phenomenon was investigated for Sm²⁺ ions-doped Al₂O₃-SiO₂ glasses prepared by the sol-gel method. The efficiency of hole-burning, burned at low temperature ~77K, was proportionally increased with the content of OH groups surrounding the rare-earth ions. The proposed mechanism for hole-burning was the optically activated rearrangement of the OH bonds surrounding the rare-earth ions. The burned-hole was thermally refilled and erased above ~200 K. On the other hand, the glasses obtained by heating in H₂ gas or irradiating with x-rays showed PSHB up to room temperature. When heated in H₂ gas, the H₂ molecules react with oxygen ions to form H₂O. Removal of the generated H₂O causes the number of oxygen ions surrounding rare-earth ions to decrease, resulting into the reduction of the ions. The hole burning in the H₂-treated glasses was performed by the electron transfer between the rare-earth ions and the trapping centers. In contrast, in the x-ray irradiated glass, it was concluded that the rear-earth ions are deuced into the divalent state by electron transfer from the oxygen defect center. The hole defect centers are trapped in oxygen ions bound with Al³⁺ ions. The spectral hole burning of the x-ray irradiated glasses could be burned by the reverse reaction of the reduction of the rare-earth ions. A short distance between the Sm²⁺ and oxygen defect centers brought a high-speed hole burning, that is, 30 times faster than in a similar H2 gas treated glass.

Oxyfluoride glasses of the compositions of 50SiO₂•50PbF₂•(5 - x)GdF₃•xErF₃ and 50SiO₂•50PbF₂•(5 - y)GdF₃•0.1NdF₃•yYbF₃•0.1(Tb, Ho, Er or Tm)F₃ in molar ratio (x =0.3 - 5 and y = 0 - 5) were developed. The oxyfluoride glasses were heat-treated at their first crystallization temperatures. Consequently, the crystals of -PbF₂:(trivalent rare-earth ions) solid solutions uniformly precipitated in the scales of 15 20 nm in diameter in silicate glass matrices. These glass-ceramics were transparent to the naked eye. The glass-ceramics gave highly efficient upconversion luminescence based on the Tb³⁺, Ho³⁺, Er³⁺ or Tm³⁺ ion under 800 and/or 980 nm light excitation. These oxyfluoride glasses can be locally changed to glass-ceramics in the forms of dots, lines, letters, planes, etc. by irradiation of various lasers. The forms written by laser irradiation can be easily read from upconversion luminescence generated by the 800 and/or 980 nm laser illumination. Thus, the present oxyfluoride glasses can be applied to an optical memory device for specific information. Plates, fibers, thin films and coating-films in which the glass-powders are embedded in inorganic and/or organic polymers are considered as the shapes of oxyfluoride glasses that can be utilized as the device.

No abstract available.

We have investigated the effect of high-pressure on the crystallization of an Li₂O-Al₂O₃-SiO₂ glass. The glass was heated for nucleation, followed by heating for crystal growth. Hydrostatic pressure of argon gas of 196 MPa was applied in either the nucleation process or the crystal growth process, and in both the processes. β-quartz solid solution was precipitated in all glass-ceramic specimens. The crystallinity of the glass-ceramics increased by applying high-pressure during the nucleation or the crystal growth process. Lattice constants of the precipitated crystal were decreased by applying high-pressure. Magnitudes of the increase of crystallinity and the decrease of lattice constants by applying pressure in the crystal growth process were larger than these in the nucleation process. Density of glass-ceramic specimens increased by applying pressure in any heat treatment. It was suggested that the increase in density is due to increase of crystallinity, decrease of lattice constant and possibly densification of glass part. The refractive index increased with increasing density. The temperature coefficient of the optical path length, dS/dT, decreased by applying pressure.

Recent research work on the preparation and characterization of hybrid organic-inorganic optical solids in this laboratory is briefly introduced. Emphasis is given to the photophysical properties of rare earth (Eu³⁺, Tb³⁺) chelates in-situ synthesized in inorganic gel glasses as well as the fluorescence probe of organics on the microstructural evolution of the hybrid materials.

Dynamical Faraday rotation measurements with pulsed magnetic fields up to ~16 T have been carried out to investigate magnetic interactions between Tb³⁺ ions in highly Tb₂O₃-concentrated borate glasses (25-40mol%). These glasses were completely paramagnetic around room temperature, while a cooling down below 100 K began to produce antiferro-couplings of magnetic moments (J = 6) of Tb³⁺ ions in local areas of the glasses due to the superexchange interactions via oxygen atoms. The modification of the magnetic structure by doping with divalent manganese ions increased the magnetic correlation temperature. It will be also given that a novel glass matrix of 5B₂O₃-3Ga₂O₃-3SiO₂-P₂O₅ has been developed in order to increase Tb₂O₃ content up to 40 mol.% in glasses.

We report on the observation of photostimulated long-lasting phosphorescence in a Tb³⁺-doped glass sample. After irradiation by an ultraviolet (UV) light at 254 nm or an 800 nm femtosecond pulsed laser, we find that the glass sample emits bright and long-lasting phosphorescence. Long-lasting phosphorescence is observed once again after further excitation by 365 nm UV light when the 254 nm UV light or the femtosecond laser-induced long-lasting phosphorescence cannot be detected. The intensity of the photostimulated long-lasting phosphorescence decreases in inverse proportion to the time. Based on absorption, emission spectra and thermoluminescence curves, we consider the photostimulated long-lasting phosphorescence to be due to the light-induced re-arrangement and thermostimulated recombination of electrons and holes in traps induced by the 254 nm UV light or the femtosecond laser at room temperature. We infer that the observed phenomenon is useful in the fabrication of rewriteable three-dimensional optical memory with ultrahigh storage density and ultrafast storage speed.

The upconversion emission spectra of Er³⁺ single doped and Er³⁺/Yb³⁺ codoped tellurite glasses with 974nm excitation were measured, the upconversion mechanism and the influence of Yb³⁺ concentration on the upconversion emission of Er³⁺ were discussed, the energy transfer efficiencies and coefficients between Yb³⁺ and Er³⁺ were calculated using the measured lifetimes.

This paper reports that upconversion phenomenon exists in Tm³⁺-doped tellurite glass by pumping with both 793nm and 1064nm lasers. Strong 785nm two-photon upconversion fluorescence of ¹G₄ → ³H₅ transition and weak three-photon upconversion 710nm, 677nm, fluorescence pumped by 793 nm Ti:Al₂O₃ laser has been observed firstly in Tm³⁺-doped tellurite glass. Upconversion has also been observed under excitation at 1064nm.

The absorption and emission properties of Yb³⁺ in numerous silica-based glasses have been investigated. The compositional dependence of the absorption cross section, the integrated absorption cross section and the stimulated emission cross section of Yb³⁺ were studied for various silica-based glass.

Nonlinear optical properties of femtosecond laser-induced micro-structures containing gold nanoparticles in silicate glasses were investigated by using Z-scan technique with 8ns pulses at 532nm. Optical limiting effects of such structures were also measured. The experimental results were found to be significantly variable for the microstructures under different induction conditions. Strong optical nonlinearities in these yielded structures can be attributed to the surface plasmon absorption of gold nanoparticles precipitated in glasses. These microstructures exhibiting large optical nonlinearities are inferred to be useful for the fabrication of integrated ultrafast optical switching and laser protection devices.

The Optical nonlinearities and optical limiting (OL) properties of Sol-gel solidified gold nanorods were investigated by using Z-scan technique and OL measurement, respectively, with nanosecond pulses at 532nm. The experimental results show that their strong nonlinear optical performances depend on the sizes of nanorods. The surface plasmon absorption is the main mechanism.

A group of of heavy germanate glasses containing BaO and/or Gd₂O₃, La₂O₃, SnO and doped with the scintillating rare earth Tb³⁺ are presented. Photoluminescence measurements are made on these glasses. The intensity of emission peaks is found proportional to the contents of Tb3+ dopants as well as of Gd3+: the former indicates that no obvious concentration quenching effect is visualized within the limits of present Tb3+ dopant while the latter is related to the enhanced energy transfer process from Gd³⁺ to Tb³⁺ centers.

Heterostructural photonic band gap materials were fabricated by sol-gel technique. The heterostructure consists of two one-dimensional periodical photonic structures with different photonic stop bands. We found that the band gap of the heterostructure was extended obviously. The new band gap is the sum of the gaps of the two periodical structures. The results match well with that calculated by transfer matrix method. We also fabricated heterostructural three-dimensional photonic structures by sub-micron spheres self-assembling method, similar result was obtained which extended the concept from one dimension to three dimension.

The optical, luminescent and stability properties of TEOS-GPTMS gel glasses doped with rhodamine B were studied in the paper. Two reversed influences of organic modifier on improving the optical quality of gel glass matrix and reinforcing the non-irradiation transitions of dye molecules was proved. Different mechanisms of thermal degradation and photo degradation were indicated, thermal oxygenation process between environmental oxygen and dye molecules for thermal degradation, and photochemistry reaction between dye and other active reactants in the matrix for photo degradation. Thermal degradation of laser dyes caused by oxidization reaction was the key destroying path of the solid dye gain medium based on the gel glass during pumped with water.

In this paper, the samples of CuSc_1-xMg_xO₂ thin films were deposited on the quartz glass substrates, using a CuSc_0.93Mg_0.07O₂ target, by rf sputtering at 120 W with a 2.0 Pa mixture gas of oxygen and argon. The gas ratio (O₂/Ar) was set to 0.0, 0.1, 0.2, 0.3, 0.4, 0.6, 0.8, 1.0. The characterization of the films was carried out using a X-ray photoelectron spectroscopy (XPS) and a X-Ray diffraction (XRD). It was found that the as-deposited films were amorphous and the Mg stoichiometry in the CuSc_1-xMg_xO₂ thin films decreased with the increase of the ratio of O₂ to Ar, the amorphous samples with the Mg=0.01 to 0.04 had conductivity of 0.015 S/cm; after postprocessing of the samples were by rapid thermal annealing (RTA) at 950 °C for 3 min. in a flowing Ar atmosphere, the samples were crystal structure with preferred (101) panel orientation but it is difficult to determine that the crystal form was of a hexagonal 2H-polytype or 3R, the oxygen stoichiometry was lower than 2, the conductivity of the RTA films varied from 0.92 to 3.8 S/cm; after oxygen was intercalated to the RTA samples under oxygen pressure of 8.0 atm. at 500 °C for 10 min., the oxygen intercalated samples had a higher conductivity than that of the RTA samples, but the transmittance of the films in the wavelength of 190-780 nm was much lower than that of the as-deposited and the RTA samples. The Seebeck coefficient showed that the conductive samples were p-type. The results obtained were discussed.

In this paper, the samples of transparent thin films have been prepared, using a 5.6 cm diameter target of CuScO₂ doped with 4.5%(mole), on quartz glass substrates by rf sputtering at 120W. The substrates were heated at 450° C during sputtering. The samples were treated by rapidly thermal annealing (RTA) for 3 minutes at 950 °C in a argon flowing atmosphere, and then the RTA samples were treated at 500° C under oxygen atmosphere at pressures ranging from 1 to 7 atm. in order to intercalate oxygen into the center of Cu triangles in the triangular Cu plane of delafossite structure. XRD, UV/VIS and XPS have been used to characterize the samples. The results showed that the structures of all the films were amorphous, the transmittance (%) of the samples in the visible region of the spectrum decreased with the increase of the oxygen stoichiometry in the films, but the conductivity increased, the Seebeck coefficient was found to be positive and varied from 378uV/K to 42uV/K, which means that the conductive samples were p-type. The results stated above were discussed.

Liquid-phase deposition technique is applied to form a silver film inside the inner-surface of silica capillary base on the method of silver mirror reaction. Using this fabrication method, we have succeeded in making hollow waveguides with a bore size of 1mm and a guide with length of as long as 2m on our self-producing apparatus. The maximum transmission efficiency of hollow-core fiber without dielectric coating can be up to 85 percent and loss can be low to 1.0dB/m.

At first, we made a approximate λ/4-shifted DFB Yb-doped fiber laser with double exposure method. The length of Yb-doped fiber is 10cm. Secondly, we treat λ/4-shifted Yb-doped DFB fiber laser with UV trimming. We observed the running characteristic of the laser with scanning F-P interferometer and oscilloscope at the same time. Finally, we obtained SLM Yb-doped λ/4-shifted DFB fiber laser. The laser threshold is 20mW. When pump power is 130mW, we have gained 25mW SLM laser at 1053nm. Finally, we obtained SLM Yb-doped λ/4-shifted DFB fiber laser. The threshold of which is 20mW. When pump power is 130mW, we obtained 25mW SLM laser at 1053nm.

The optical properties of rare-earth organic complexes-doped poly(methyl methacrylates)(PMMA) have been studied because of their great prospect of application in optical devices, such as optical fibers, fiber lasers, amplifiers and waveguides. Eu³⁺, Pr³⁺ and Tb³⁺ ions were encapsulated in tri(dibenzolymethane)(DBM) and tri(thenoyltrifuoroacetone)(TTA) chelates, then Eu³⁺ complexes were doped in MMA before the polymerization, and stirred thoroughly during the polymerization. These complexes were characterized by elementary analysis, FT-IR, XPS and ICP, and fluorescent properties of rare earth complexes-doped PMMA were measured by fluorescence spectrometer. Analysis reveals that Eu(TTA)₃ is a promising dopant for use in rare-earth-doped PMMA in the research, the complex can be doped to high concentrations in PMMA systems without quenching, providing means for polymer amplification devices. For the rare-earth-doped PMMA samples, an effective energy transfer between the ligands and rare-earth ions is observed and discussed. To our knowledge, the effect of molecular weight of PMMA on the fluorescent properties of rare-earth-doped PMMA has not been reported, and the result indicates that the larger the molecular weight of PMMA is, the better the fluorescent property of the system.

No abstract available.

Luminescence behavior of Eu(TTFA)3 doped B₂O₃-SiO₂ films prepared by sol-gel process has been investigated. With the increase of heat treatment temperature and time, the Eu(TTFA)₃ complexes were gradually synthesized and luminescence intensity gradually increased. There existed an efficient luminescence layer in the Eu(TTFA)₃ doped B₂O₃-SiO₂ films. The thickness of the efficient luminescence layer depends significantly on the B₂O₃ content of the gel. The thickness of the efficient luminescence layer decreased obviously with increase of B₂O₃ contents in B₂O₃-SiO₂ gel films. The influence of the film thickness on the transmitted intensity of the Eu(TTFA)₃ doped B₂O₃-SiO₂ gel films indicated that the thickness of the efficient luminescence layer of the Eu(TTFA)₃ doped B₂O₃-SiO₂ films depended on the absorption of incident excitation light by the organic ligands in the gel film.

Infrared fibers, based on low phonon chalcogenide glasses have been developed in order to measure the infrared signatures of several chemical and biological materials. It is shown, that in tapering the fibers, the sensitivity and flexibility are significantly improved, allowing in situ experiments, in remote conditions or on biological tissues. Information on soil contamination, for environment protection, as well as detection of anomalies of on liver mice metabolism, are described.

Er-doped silica glasses (5000ppm Er/Si mol) were prepared by sol-gel method. Gel samples underwent dehydration in carbon tetrachloride environment. It shows that carbon tetrachloride can remove hydroxyl groups effectively. As a result, I_13/2-I_15/2 fluorescence lifetime rises considerably. It is also found that fluorescence lifetime is strongly dependent on OH concentration. For samples annealed in carbon tetrachloride at 900°C, fluorescence lifetime as long as 6ms was reached.

The synthesis and characterization of polymer composite system containing quantum-confined CdS nanoparticles entrapped in an Acrylic acid-hydroxypropyl acrylate copolymer (AC-HAC) is reported. The results showed that the CdS nanoparticles had an average particles size of 3.6nm in diameter and the band edge (λ_edge) of the entrapped CdS nanoparticles was 391nm. The colloidal solution exhibited a band-edge emission peak around 420nm due to the surface passivation. In order to observe the stability of the colloidal solution, it was exposed to air at room temperature for certain days. It was found that the colloidal solution remained as a colloidal solution of CdS nanoparticles even after 65 days exposition.

In this work, we developed a new mould fabrication technique to prepare a novel solid state dye laser gain medium with sandwich structure. Using the core of dye doped TEOS-GPTMS system ORMOSIL gel glass, and the moulds consisting of two optical coated K9 glasses with the thickness of 1mm, we obtained this composite laser gain medium. Comparing with the same laser gain medium without moulds by conventional method, the laser performance of this resulting medium has been greatly improved: the laser life time increases by 1 order of magnitude, the slope efficiency increases 12% and the laser threshold decreased 5%. Further reformations on laser pumping device made the composite solid state dye laser nearly reach practical levels.

Photonic crystals made of metals such as silver and gold have been theoretically demonstrated to exist complete photonic band gaps (CPBG). We studied the preparation of metallic-dielectric spheres, which have the same effect as metals and can be used to fabricate a new type of photonic crystals. By using the Electroless Plating Method, SiO₂ spheres 300nm in diameter were coated with an about 20nm silver layer. The derived samples precoated with copper showed more homogeneous and much thinner silver layers compared with the directly coated ones. Our experiments also indicated that the sensitization and activation processes were necessary for the copper coating processes, although had little effect on the silver particle sizes as well as the layers thickness. Nuclear-growth mechanism is responsible for the deposition of both silver and copper nanoparticles on the surface of the spheres.

Emissions at 1.3µm and mid-infrared region from several rare-earths ions doped into PbO-Bi2O3-Ga2O3 glasses were investigated. Lifetime of the Pr3+:1G4 level was 53µs with a quantum efficiency of 9%. Emission at 2.73µm from Er3+, which is normally quenched in oxide glass, was evident and the lifetime of the upper emission level was approximately 900µs. Thermal stability of PbO-Bi2O3-Ga2O3 glass was considerably improved by adding 10 mole % of GeO2. Doping of Tm3+ and Ho3+ showed potentials for S-band fiber-optic amplification.