Phosphor in glass (PiG) employing Ce:Y₃Al₅O₁₂ (YAG)-doped boro-bismuthate glass via low-temperature co-sintering technology was successfully prepared, using Bi₂O₃-B₂O₃-ZnO glass as the base material. The photoluminescence (PL) of PiG co-sintered at times ranging from 20 min to 60 min at 700°C was investigated. As a result, the relative PL intensity of PiG under a reducing atmosphere of CO showed significant enhancement of about 7–14 times that under air atmosphere sintering for 20–50 min. The PL intensity decreased gradually with the co-sintering time, which may be due to the corrosion of the YAG lattice structure.

We report on the elemental redistribution behavior in oxyfluoride glasses with a high repetition rate near-infrared femtosecond laser. Elemental analysis by an electro-probe microanalyzer demonstrates that the redistributions of Ca²⁺ and Yb³⁺ ions change dramatically with pulse energy, which are quite different compared with previous reported results. Confocal fluorescence spectra of Yb³⁺ ions demonstrate that the luminescence intensity changes obviously with the elemental redistribution. The mechanism of the observed phenomenon is discussed. This observation may have potential applications in the fabrication of micro-optical devices.

Connected-annular-rods photonic crystals (CARPCs) in both triangular and square lattices are proposed to enhance the two-dimensional complete photonic bandgap (CPBG) for chalcogenide material systems with moderate refractive index contrast. For the typical chalcogenide-glass–air system with an index contrast of 2.8:1, the optimized square lattice CARPC exhibits a significantly larger normalized CPBG of about 13.50%, though the use of triangular lattice CARPC is unable to enhance the CPBG. It is almost twice as large as our previously reported result [IEEE J. Sel. Top. Quantum Electron.22, 4900108 (2016)IJSQEN1077-260X10.1109/JSTQE.2015.2422997]. Moreover, the CPBG of the square-lattice CARPC could remain until an index contrast as low as 2.24:1. The result not only favors wideband CPBG applications for index contrast systems near 2.8:1, but also makes various optical applications that are dependent on CPBG possible for more widely refractive index contrast systems.

Bismuth (Bi)-doped laser glasses and fiber devices have aroused wide attentions due to their unique potential to work in the new spectral range of 1 to 1.8 μm traditional laser ions, such as rare earth, cannot reach. Current Bi-doped silica glass fibers have to be made by modified chemical vapor deposition at a temperature higher than 2000°C. This unavoidably leads to the tremendous loss of Bi by evaporation, since the temperature is several hundred degrees Celsius higher than the Bi boiling temperature, and, therefore, trace Bi (～50 ppm) resides within the final product of silica fiber. So, the gain of such fiber is usually extremely low. One of the solutions is to make the fibers at a temperature much lower than the boiling temperature of Bi. The challenge for this is to find a lower melting point glass, which can stabilize Bi in the near infrared emission center and, meanwhile, does not lose glass transparency during fiber fabrication. None of previously reported Bi-doped multicomponent glasses can meet the prerequisite. Here, we, after hundreds of trials on optimization over glass components, activator content, melting temperature, etc., find a novel Bi-doped gallogermanate glass, which shows good tolerance to thermal impact and can accommodate a higher content of Bi. Consequently, we successfully manufacture the germanate fiber by a rod-in-tube technique at 850°C. The fiber exhibits similar luminescence to the bulk glass, and it shows saturated absorption at 808 nm rather than 980 nm as the incident power becomes higher than 4 W. Amplified spontaneous emissions are observed upon the pumps of either 980 or 1064 nm from germanate fiber.

In this work, a hybrid structure consisting of a multicomponent germanate glass microsphere containing bismuth as a gain medium is proposed and presented. The bismuth-doped germanate glass microspheres were fabricated from a glass fiber tip with no precipitation of the bismuth metal. Coupling with a fiber taper, the bismuth-doped microsphere single-mode laser was observed to lase at around 1305.8 nm using 808 nm excitation. The low threshold of absorbed pump power at 215 μW makes this microlaser appealing for various applications, including tunable lasers for a range of purposes in telecommunication, biomedical, and optical information processing.

Tb3+ and Sn2+ co-doped strontium phosphate glasses are prepared and their unique photoluminescence (PL) properties for deep UV excitation are investigated. With the co-doped Sn2+ ions, Tb3+ keeps the original PL behaviors under near UV excitation while its PL action for deep UV excitation is enhanced tremendously. PL emission and excitation spectra demonstrate the sensitization role of Sn2+ on the Tb3+ emissions for deep UV excitation that is associated with the strong deep UV absorption of Sn2+ for greatly enhancing the resonance of the Tb3+ excitation with the deep UV light source. The decay curves of Sn2+ and Tb3+ emissions for both singly doped and co-doped samples are single exponentially well fitted with almost the same emission lifetime (τ) values in the microsecond and millisecond time regimes, respectively, confirming that Sn2+ and Tb3+ act as an independent activator in the present phosphate glass matrix while an involved energy

In this paper, we present the luminescent properties of Tm3+∕Ho3+ co-doped new glass. A series of silicategermanate glass was prepared by the conventional melt-quenching method. In the Tm3+∕Ho3+ co-doped silicategermanate glass, a strong emission of 2 μm originating from the Ho3+:5I7 → 5I8 transition can be observed under conventional 808 nm pumping. The characteristic temperatures, structure, and absorption spectra have been measured. The radiative properties of Ho33+ in the prepared glass were calculated. The emission cross section of Ho33+ ions transition can reach 4.78 × 10?21 cm2 around 2 μm, and the FWHM is as high as 153 nm. The energy transfer efficiency between Ho3+ and Tm3+ has a large value (52%), which indicates the Tm3+∕Ho3+ co-doped silicategermanate glass is a suitable candidate for the 2 μm laser. Moreover, the energy transfer mechanism between Tm3+ and Ho3+ ions was investigated.(61370049, 61308090, 61405182, 51172252, 51372235, 51472225); International Science & Technology Cooperation Program of China (2013DFE63070); Public TechnicalInternational Cooperation Project of the Science Technology Department of Zhejiang Province (2015c340009).

Broadband (1.6–18 THz) terahertz time-domain spectroscopy (THz-TDS) and time-resolved terahertz spectroscopy (TRTS) were performed on a 54 μm thick chalcogenide glass (As30Se30Te40) sample with a two-color laser-induced air plasma THz system in transmission and reflection modes, respectively. Two absorption bands at 2–3 and 5–8 THz were observed. TRTS reveals an ultrafast relaxation process of the photoinduced carrier response, well described by a rate equation model with a finite concentration of mid-bandgap trap states for self-trapped excitons. The photoinduced conductivity can be well described by the Drude–Smith conductivity model with a carrier scattering time of 12–17 fs, and we observe significant carrier localization effects. A fast refractive index change was observed 100 fs before the conductivity reached its maximum, with 2 orders of magnitude larger amplitude than expected for the optically induced THz Kerr effect, indicating that free carriers are responsible for the transient index change.

Yb-doped silica glasses containing low, medium, and high content of OH are prepared through nanoporous glass sintering technology. High-OH sample exhibits better X-ray irradiation resistivity than low- and medium-OH samples. After irradiation, OH content of low- and medium-OH samples increases 37.5% and 11%, respectively; in contrast, OH content of high-OH sample decreases dramatically. The different OH content changes among the samples are discussed regarding the proposed inter-conversion reactions involving Si-H and Si-OH during the irradiation.