Co-doped Silica Glass Research Articles

Yb/P/Al共掺双包层光纤的制备与激光性能

Yb/P/Al codoped silica glass preforms are fabricated by MCVD process combined with the solution doping technique.Highly and homogeneously doping of Yb3+ is realized by optimization of the core composition and fabrication process.The Yb2O3 concentration in preform core is up to ~4 wt.% and Yb3+ fluorescence lifetime at 1080nm reaches 1 780 μs.Double-clad fibers with octagonal inner cladding are successfully drawn from the preform,the fiber core diameter is 7.5 μm and the clad absorption coefficicent is up to ~5 dB/m@976 nm.The operation of the cladding pumped all-fiber laser is demonstrated using Yb-doped double-clad fibers.Fiber lasers with output power of 5.15 W and slope efficiency of 76% are obtained.

Photoluminescence of sol-gel silica fiber preform doped with Bismuth-containing heterotrinuclear complex

A monolithic Bismuth-Aluminium codoped silica glass was prepared from nano-porous silica xerogels using a conventional solution doping technique with a heterotrinuclear complex and subsequent sintering. This novel approach enabled the preparation of the silica glass which contains a single luminescent center, namely an Al-connected Bi-center.

Al3+/Eu2+共掺杂高硅氧玻璃的荧光特性

Al³⁺/Eu²⁺共掺杂高硅氧玻璃的荧光特性

Luminescence of Yb2+, Yb3+ co-doped silica glass for white light source

Yb2+, Yb3+ co-doped silica glasses were prepared by solid state reaction under vacuum condition for the first time. The luminescence properties of Yb2+-doped silica glass were investigated. There are four strong absorption bands in the Ultraviolet (UV) light region due to the 4f14–4f135d1 transition of the Yb2+ ions. The main emission wavelength of the Yb2+-doped silica glass was around 530nm by the excited wavelength of 398nm. The full width at half maximum (FWHM) of the excitation and emission bands were 137nm, 165nm respectively. The results suggest the Yb2+-doped silica glasses may be the potential medium for white light sources based on near UV LED chip.

希土類-リン共ドープシリカガラスのゾル-ゲル合成と発光特性

希土類-リン共ドープシリカガラスのゾル-ゲル合成と発光特性

UV laser induced transmission change of pure and doped silica glass

Pure and F, GeO2-doped silica glass cut from fiber preforms prepared by plasma assisted chemical vapor deposition(PCVD) were investigated by ultraviolet absorption spectroscopy. The ultraviolet absorption characteristics of these glasses were also studied after UV laser irradiation and heating treatment. It was found that absorption band near 240 nm assigned to GODC was found both in GeO2-doped and F-GeO2 co-doped silica glass, but absorption intensity of the latter was lower than that of the former. It’s because F can react with GODC and GeE’ simultaneously and reduce their concentration. After irradiation, UV absorption change of F-GeO2 co-doped silica glass was weaker than that of GeO2-doped silica glass,it thus can be concluded that introduction of F could depress the UV absorption of GeO2-doped silica core effectively.

Yb3+:Al3+:sol–gel silica glass fiber laser

For the first time, an ytterbium-doped aluminum co-doped silica glass fiber laser has been produced by the sol–gel technique. The laser has a threshold of 79.7mW launched power and a slope efficiency of 73%. The maximum output of 34.2mW was limited by the available pump power. The emission is tunable from 1033 to 1108nm. The losses of the fiber at a wavelength of 1100nm are 31.2±2.2dB/km.

Study of the Si-nanocluster to Er3+ energy transfer dynamics using a double-pulse experiment

Abstract We present investigations of the energy transfer dynamics after short-pulse excitation in co-doped silica glasses containing silicon nanoclusters (Si-nc) and Er 3+ ions. Using a double pulse setup we find evidence for the occurrence of a fast (few hundreds nanoseconds) Si-nc recovery process in samples containing well-defined Si aggregates, whereas a slower recovery is found in a sample annealed for a very short time. The influence of Auger quenching processes taking place between Si-nc and Er 3+ in the excited states on the energy transfer process is also shown and discussed.

Probe of the Si nanoclusters to Er3+ energy transfer dynamics by double-pulse excitation

In this letter the dynamics of the energy transfer (ET) process from amorphous silicon nanoclusters (Si-nc) to Er3+ ions is investigated in co-doped silica glasses. Using a double pulse setup the recovery time of the sensitizing effect is monitored and direct evidence is found for the occurrence of a fast (few hundreds ns) ET process in a sample containing large (2nm) aggregates, while a slower transfer time of few microseconds is revealed in a sample containing very small (<1nm) aggregates.

Reduction of Eu3 + to Eu2 + in Al-Codoped Silica Glasses Fabricated by the Sol-Gel Technique and CO2-Laser Processing

The spectroscopic properties of europium in aluminium codoped silica glasses produced by the sol-gel technique have been studied with respect to the dopant concentrations and the thermal processing applied to the samples. After thermal annealing at temperatures up to 950_°C the bright red fluorescence around 613 nm characteristic for the trivalent europium ions (Eu3 +) has been observed. The lifetime was measured to be 0.1–2.4 ms depending on dopant concentrations and thermal treatment. Subsequent CO2-laser processing in air (short time remelting) gave rise to a bright blue fluorescence consisting of two broad bands, lying around 450 and 490 nm, with their peak position depending on the ratio between the aluminium and europium concentrations. The fluorescence lifetimes were found to be shorter than 1 μ s. This blue fluorescence is attributed to the divalent europium ion (Eu2 +), leading to the conclusion that the CO2-laser processing of europium doped alumina-silica glasses resulted in the reduction of the trivalent to the divalent europium ion. Laser processing could therefore be a valid alternative to conventional thermal annealing for the generation of Eu2 + in alumina-silica glasses.

Optical absorption of Co2+-doped silica gel-derived glasses

Abstract Monolithic samples of silica and Co-doped silica gels were obtained by the sol–gel method and heat-treated at temperatures from 40 to 1000 °C. The colors of Co-doped silica samples depended on heat-treatment temperature. Ultraviolet, visible and near-infrared (NIR) absorption spectra of the samples heated at different temperatures were recorded and compared with those of undoped silica samples. Results showed that 0.4 wt.% Co-doped silica samples heated at temperatures ranging 750–1000 °C exhibited broad absorption band in the range of 1200–1600 nm, and the intensity of the absorption band increased with heat-treatment temperatures. Co-doped silica glass is potential to be used as a kind of laser passive Q-switching material in NIR range.

Spontaneous reduction of Eu 3+ ion in Al co-doped sol–gel silica matrix during densification

Eu and Eu-Al co-doped silica glasses have been prepared by impregnating the pores of a base catalysed tetraethylorthosilicate (TEOS) gel with the nitrate salt of Eu and Al and subsequent densification around 1125 to 1150°C. Absorption, emission and excitation spectra of these glasses indicate that Eu 3+ ions are spontaneously reduced to Eu 2+ in the presence of Al 3+ during sintering of the glasses above 1000°C.

Preparation and characterisation of monolithic Pr-doped silica glasses by a sol–gel method

Pr–Al co-doped silica glasses have been prepared using Pr(NO 3) 3 6H 2O, Al(NO 3) 3 9H 2O and a sol of fumed silica and HNO 3 acidified Si(OC 2H 5) 4 as starting materials. The glasses were characterised by density, transmission electron microscope (TEM), EDAX, refractive index, linear shrinkage, absorption and fluorescence spectra. The glasses were also examined in relation to total –OH content with Pr-concentration. Aluminium co-doping modifies the optical properties of the Pr-doped glasses.

Scattering property of F and GeO2 codoped silica glasses

The Rayleigh scattering coefficients of fluorine (F) and GeO2 codoped silica glasses are investigated experimentally. It is found that the Rayleigh scattering coefficients of F and GeO2 codoped silica glasses increase linearly with GeO2 dopant concentration and parabolically with F dopant concentration.

Viscosity of F and GeO2 codoped silica glass

The dopant concentration dependence of the viscosity of fluorine (F) and GeO/sub 2/ codoped silica glass is investigated experimentally. The viscosity of these glasses at various dopant concentrations is measured using the drawing method in the 1700-2000 degrees C temperature range. The change in the viscosity logarithm of F and GeO/sub 2/ codoped silica glass was found to be the linear sum of the changes induced individually by F and GeO/sub 2/.

Preparation of Nd-doped silica glasses by the sol-gel method

Monolithic NdAl co-doped silica glasses were prepared by the sol-gel method with double metal alkoxide of neodymium and aluminum, and their fluorescence properties were evaluated and compared with those of Nd-doped silica glasses. The dispersibility of Nd 3+ in the NdAl co-doped silica glasses increases significantly because the structure of the double metal alkoxide is maintained until the final glassy state, with a higher Nd concentration of up to 4 mol% as Nd 2O 3. It was found that concentration quenching caused by clustering of Nd 3+, as shown in the case of glasses with a relatively higher Nd concentration, was controlled. Aerogel prepared with a CO 2 extractor had the merit of removing the OH groups. Because of the large pore size and the resultant higher densification temperature, a relatively longer fluorescent lifetime was observed.