Effect of Fe impurity on the optical loss of Nd-doped phosphate laser glass

The optical loss coefficient at 1053-nm wavelength, influenced by Fe ions in N31-type Nd-doped phosphate laser glass, was determined precisely and analyzed in detail. It is found that the optical loss coefficient per unit of Fe concentration (cm^(-1)/ppmw) increases with Fe concentration in the range of 0---300 ppmw, but it approaches a constant as the Fe concentration is larger than 300 ppmw. Such a concentration effect is due to a shift in the redox equilibrium between Fe3+ and Fe2+ ions in the glass. The effect of oxygen pressure, temperature, and variable valence states of other metal ions in glass samples on the optical loss is also discussed.

Er3+ and Yb3+ codoped phosphate laser glass for high power flashlamp pumping

A novel Vb(3+)-Er-(3+) codoped phosphate glass for high power flashlamp pumping and high repetition rate laser at 1.54 mu m, designated EAT5-2, is developed. The weight-loss rate of is 1.3 x 10(-5) gcm(-2) h(-1) in boiling water, which is comparable to Kigre's QX-Er glass. Some spectroscopic parameters are analysed by Judd-Ofelt theory and McCumber theory The emission cross section is calculated to be 0.73 x 10(-20) cm(2). The thermo-mechanical properties of EAT5-2 are modified after an ion-exchange chemical strengthening process in a KNO3/NaNO3 molten salt bath. The thresholds for optical damage from the flashlamp pumping are tested on glass rods. A repetition rate of 15 Hz is achieved for chemically strengthened glass. The laser experimental results at. 1.54 mu m from flashlamp pumping are also reported.

Microstructure of the crystals generated in borate glass irradiated by femtosecond laser pulses

In this study, we examined the microstructure of crystals generated in borate glass by femtosecond laser irradiation (FSLI). The distribution of the high-temperature and low-temperature phases of barium metaborate crystals produced in the borate glass is analyzed using Raman spectroscopy. We then propose the possible mechanism for the generation of crystals in glass by FSLI.

Self-formation of quasiperiodic void structure in CaF2 induced by femtosecond laser irradiation

We report the self-formation of quasiperiodic void structure with the length of several hundred micrometers inside the CaF2 crystal. The quasiperiodical voids along the propagation direction of the laser beam were formed spontaneously after the irradiation of a single femtosecond laser beam which was focused at a fixed point inside the crystal sample. The length of the void array varied with the focal depth beneath the sample surface. The possible mechanism of the self-formed void structure was discussed. (c) 2007 American Institute of Physics.

Study of hybrid TiO2/ormosil films doped with laser dyes

TiO2/ormosil films doped with laser dyes have been prepared by the sol-gel method. Spectroscopic properties of the entrapped dyes are studied by the absorption and emission techniques. The results indicate that the absorption and fluorescence spectra of kiton red depend strongly on the properties of the ormosil matrices. The heat-treatment of the kiton red-doped film obviously leads to the increasing fluorescence intensity and the largest fluorescence intensity is obtained after heat-treatment of 150 degrees C for 2 h. However, the fluorescence intensity of the rhodamine 6G-doped film decreases with the increase of the heat-treatment temperature. (c) 2005 Elsevier B.V. All rights reserved.

Space-selective co-precipitation of silver and gold nanoparticles in femtosecond laser pulses irradiated Ag+, Au3+ co-doped silicate glass

We report on space-selective co-precipitation of silver and gold nanoparticles in Ag+, Au3+ co-doped silicate glasses by irradiation of femtosecond laser pulses and subsequent annealing at high temperatures. The color of the irradiated area in the glass sample changed from yellow to red with the increase of the annealing temperature. The effects of average laser power and annealing temperature on precipitation of the nanoparticles were investigated. A reasonable mechanism was proposed to explain the observed phenomena. (c) 2006 Elsevier Ltd. All rights reserved.

Laser bidezko tenplaketa jasandako piezen distortsio termikoen analisia.

[EU]Proiektu honen bidez, laser bidezko tenplaketaren ondoriozko piezen gainazalen distortsioaren neurketa kuantitatiboa eta tratamendu honegatik eratorri daitezkeen hondar tentsioen azterketa egin nahi izan da. Hauxe burutzeko hondar tentsioen neurketarako Contour metodoa erabili da, elektro-higadurako ebaketa eginez. IGET Bilboko mekanikako tailerreko ingurugiroan eta bertako langileen inbestigazio lerroetan barneratzeko helburuz, laser tenplaketa tratamenduen azterketan lagungarria izateko xedearekin aurrera eraman da proiektu hau.

Demonstration of microfiber knot laser

The authors demonstrate a 1.5 mu m wavelength microfiber laser formed by tightening a doped microfiber into a knot in air. The 2-mm-diameter knot, assembled using a 3.8-mu m-diameter microfiber that is directly drawn from Er:Yb-doped phosphate glass, serves as both active medium and resonating cavity for lasing. Single-longitudinal-mode laser with threshold of about 5 mW and output power higher than 8 mu W is obtained. Their initial results suggest a simple approach to highly compact lasers based on doped microscale optical fibers. (c) 2006 American Institute of Physics.

The influence of OH groups on laser performance in phosphate glasses

Because of the influence of OH groups in phosphate glasses on the radiation of rare-earth ions, the laser performance is degraded. The laser efficiency and the small signal gain experiment of several phosphate glass samples have been done, the concentration of OH groups in glasses was calculated from the measured absorption coefficient at 3.47 μm. It is shown that the concentration of OH groups in phosphate glasses can seriously influence the laser output characteristics, and the OH groups have worse influence on the laser amplifier than laser oscillator.

UV-blue upconverted emission from Nd3+-doped InF3-based heavy-metal fluoride glasses for blue upconversion fibre laser

We report spectral properties and thermal stability of Nd3+-doped InF3-based heavy-metal fluoride glasses. Fluoroindate glasses in the chemical compositions (in mol%) of (38-x)InF3-16BaF(2)-20ZnF(2)-20SrF(2)-3GdF(3)-1GaF(3-)2NaF-xNdF(3) (x = 0.1, 0.5, 1, 2, 3) have been prepared under a controlled atmosphere in a dry box. Strong UVblue upconversion emission from a green excitation wavelength has been observed and the involved mechanisms have been explained. Near-infrared emission occurs simultaneously upon excitation of the UV-blue upconversion emissions with a cw Ar(+)laser. The upconversion spectra have revealed four dominant emissions at 354, 380, 412 and 449 nm, which belong to the transitions of D-4(3/2) -> I-4(9/2), D-4(3/2) -> I-4(11/2) and P-2(3/2) -> I-4(9/2), D-4(3/2) -> I-4(13/2) and P-2(3/2) -> I-4(11/2), D-4(3/2) -> I-4(15/2) and P-2(3/2) -> I-4(13/2), respectively.

Upconversion luminescence of Ce3+ doped BK7 glass by femtosecond laser irradiation

Near-infrared to visible upconversion luminescence was observed in a multicomponent silicate (BK7) glass containing Ce3+ ions under focused infrared femtosecond laser irradiation. The emission spectra show that the upconversion luminescence comes from the 4f-5d transition of the Ce3+ ions. The relationship between the intensity of the Ce3+ emission and the pump power reveals that a three-photon absorption predominates in the conversion process from the near-infrared into the blue luminescence. The analysis of the upconversion mechanism suggests that the upconversion luminescence may come from a three-photon simultaneous absorption that leads to a population of the 5d level in which the characteristic luminescence occurs.