Jinyan Li

Ce-Tb-Mn co-doped white light emitting glasses suitable for long-wavelength UV excitation

We report on a new kind of white light emitting glass suitable for long-wavelength ultraviolet excitation by simultaneously emitting blue, green and red fluorescence, which is fabricated by melting of Ce(3+)-Tb(3+)-Mn(2+) co-doped borosilicate glass. The spectroscopic properties of singly, doubly and triply doped glasses have been reported and the energy transfer from Ce(3+) to Tb(3+) and Mn(2+) has also been investigated. By adjusting the concentration of different co-dopants, we obtained the ideal white light emitting borosilicate glass with the color coordinate (x = 0.318, y = 0.333).

A compact seven-core photonic crystal fiber supercontinuum source with 42.3 W output power

We have fabricated a new type of seven-core photonic crystal fiber and demonstrated its all-fiber supercontinuum source pumped with a ytterbium-doped fiber master oscillator power amplifier. The generated supercontinuum covers the wavelength range from 720?nm to beyond 1700?nm, with an output power of 42.3?W. It is the first high-power all-fiber SC source based on seven-core photonic crystal fiber.

Tailoring of clusters of active ions in sintered nanoporous silica glass for white light luminescence

To tailor clusters of active ions in glasses is laborious but critical for obtaining high efficient luminescence. Here, we present a facile method to tailor clusters of active ions by using one kind of porous host, the nanoporous silica glass. The white light-emitting glasses were prepared by sintering of nanoporous silica glasses impregnated with Ce3+, Tb3+, Mn2+ and Al3+ ions. The combination of blue, green and red emissions of Ce3+, Tb3+ and Mn2+ ions in the glasses under ultraviolet light excitation create white light emissions. The fluorescence of the glasses under long-wavelength ultraviolet excitation are dependent on energy transfer processes between the active ions; and the Al3+ plays a key role in adjusting of the energy transfer processes.

An Ultra-Sensitive Magnetic Field Sensor Based on Extrinsic Fiber-Optic Fabry–Perot Interferometer and Terfenol-D

We report a fiber-optic magnetic field sensor with ultra-high sensitivity based on a precisely configured extrinsic fiber-optic Fabry-Perot interferometer (EFFPI) and Terfenol-D slab. The EFFPI was simply formed by placing two well-cleaved single-mode fibers with carefully designed spacing and it was bonded to the surface of a Terfenol-D slab by epoxy resin. The experiments demonstrate good linear relationship between the applied magnetic field strength and the wavelength shift up to 560 Oe and the measurement range is only limited by the available bandwidth of the light source. The maximal sensitivity of the magnetic field measured by the proposed sensor is 854.73 pm/Oe through monitoring the shift of wavelength dip of the spectrum reflected from the EFFPI, which is significantly larger than most of the reported results. We also evaluated the repeatability of the proposed sensor and the performance of the proposed sensor working at a direct-current (dc)-biased magnetic field. Results indicated that the proposed fiber-optic magnetic field sensor exhibits good restorable measurement performance up to 140 Oe and a preapplied dc magnetic field can be used to extend the linear measurement dynamic range.

Enhanced green luminescence in Ce-Tb-Ca codoped sintered porous glass.

We report on a new kind of green-emitting high silica luminous glass, which is fabricated by sintering of Ce(3+)-Tb(3+) co-doped porous glass. The spectra show that there are energy transfer between Ce(3+) and Tb(3+), and cross-relaxation between (5)D(3) and (5)D(4) energy level of Tb(3+). The energy transfer process can be adjusted by addition of Ca(2+) into the Ce(3+)-Tb(3+) co-doped porous glass, and the transfer rate can be enhanced about four times than that of Ce(3+)-Tb(3+) co-doped porous glass. The role of Ca(2+) has been discussed, and the fluorescence decay curve reveals that the Ca(2+) play an important role in energy transfer.

Effect of Yb 3+ concentration on the broadband emission intensity and peak wavelength shift in Yb/Bi ions co-doped silica-based glasses

The effect of Yb(3+) concentration on the broadband emission intensity and peak wavelength shift in Yb/Bi ions co-doped silicate glasses is investigated. The optimal Bi(2)O(3) concentration range is about 2.0-2.5 mol% in 65SiO(2)-10Al(2)O(3)-25CaO matrix (SAC glasses). For Yb/Bi codoped SAC glasses, the maximum emission intensity excited by 980 nm LD is ~30 times and 1.5 times higher than that of single Bi-doped SAC glasses excited by 980 nm and 808 nm LD, respectively, the peak emission shows obvious red-shift from 1185 nm to 1235 nm band with the Yb(2)O(3) concentration change from 0 to 3.0 mol%. For the same Yb(2)O(3) concentration in SAC glasses, the measured fluorescence lifetime near 1020 nm of single Yb(3+)-doped glasses is longer than that of Yb/Bi codoping glasses, which implyes the efficient energy transfer from Yb(3+) to Bi(n+) in SAC glasses. The results indicate Yb(2)O(3) can be induced into the bismuth-doped silicate glasses to enhance the emission intensity and control the peak wavelength.

Investigation on radiation resistance of Er/Ce co-doped silicate glasses under 5 kGy gamma-ray irradiation

Various Er/Ce co-doped SiO2-Al2O3-CaO glasses are prepared by the melt-quenching method. The radiation resistance of Er/Ce co-doped glasses is investigated under 5 kGy gamma-ray irradiation. The absorption spectra, up-conversion spectra, fluorescence intensity and lifetime of Er/Ce co-doped glasses before and after irradiation are measured and analyzed in details. The radiation induced absorption (RIA) of the Er/Ce co-doped silicate glasses can be suppressed due to Ce ions co-doping. The fluorescence intensity and lifetime of Er/Ce co-doped glasses have no apparent change after irradiation. Furthermore, the possible mechanism of Ce effect on the radiation resistance improvement is discussed. The result indicates that Er doped glasses with an optimal Ce concentration introduction can be used as active medias for radiation-resistant materials in harsh radiation environments.

Temperature compensated magnetic field sensing using dual S-bend structured optical fiber modal interferometer cascaded with fiber Bragg grating

A temperature compensated magnetic field strength optical fiber sensor has been proposed and experimentally demonstrated. A fiber Bragg grating (FBG) is cascaded to modal interferometer (MI), which is fabricated by dual S-bend splicing between thin fiber (TF) and single mode fiber (SMF) with intentionally controlled misalignment between cores. We established a modified numerical model to describe the multi-mode interference of this exceptional S-bend and misalignment structure, together with the simulation based on beam propagation method to gain insight into its operation mechanism. The FBG is used to interrogate the temperature change, and then compensate the perturbation of temperature on transmission of the MI. Thanks to the proposed dual S-bend structure and the diameter-thinned TF used here; we have obtained high magnetic sensitivity of -0.0678 dB/Oe using only 4 mm TF after the elimination of ambient temperature change.

All-Fiber-Integrated High-Power Supercontinuum Sources Based on Multi-Core Photonic Crystal Fibers

The obstacles of power scaling the supercontinuum (SC) source based on single-core photonic crystal fiber (PCF) are analyzed. The combination of high-power fiber lasers and multi-core PCFs would be a feasible method to obtain an all-fiber-integrated high-power broadband SC source (covering visible range). In this paper, we present a comprehensive study of high-power SC generation in multi-core PCFs. Comparative experiments are performed by using a high-power pulse-repetition-rate-tunable picosecond fiber laser to pump two kinds of home-made seven-core PCFs. The influences of PCF structure (fiber dispersion property) and pulse repetition rate (pulse peak power) on the SC generation in multi-core PCFs are investigated in detail. When the picosecond fiber laser at a pulse repetition rate of 1.9 GHz is adopted as the pump, 116 W SC spanning from 800 to 1700 nm is generated in 1# seven-core PCF. Also 64 W visible SC spanning at least 500-1700 nm is demonstrated in 2# seven-core PCF at a pump pulse repetition rate of 480 MHz. The potential of extending the spectral range and scaling the output power for the SC source based on multi-core PCFs are analyzed and discussed.

A hollow beam supercontinuum generation by the supermode superposition in a GeO 2 doped triangular-core photonic crystal fiber

A GeO2 doped triangular-core photonic-crystal fiber (PCF) is designed and fabricated to allow the generation of a hollow beam through a nonlinear-optical transformation by femtosecond pulses at 1040 nm from a high power Yb-doped PCF laser oscillator. The hollow beam supercontinuum is obtained at far field by adjusting incident light polarization to excite the high order supermode, behaving as a mode convertor. The supercontinuum ranging from 540 to 1540 nm is achieved with an average power of 1.04 W.