Treatment of large bone defects derived from bone tumor surgery is typically performed in multiple separate operations, such as hyperthermia to extinguish residual malignant cells or implanting bioactive materials to initiate apatite remineralization for tissue repair; it is very challenging to combine these functions into a material. Herein, we report the first photothermal (PT) effect in bismuth (Bi)-doped glasses. On the basis of this discovery, we have developed a new type of Bi-doped bioactive glass that integrates both functions, thus reducing the number of treatment cycles. We demonstrate that Bi-doped bioglasses (BGs) provide high PT efficiency, potentially facilitating photoinduced hyperthermia and bioactivity to allow bone tissue remineralization. The PT effect of Bi-doped BGs can be effectively controlled by managing radiative and non-radiative processes of the active Bi species by quenching photoluminescence (PL) or depolymerizing glass networks. In vitro studies demonstrate that such glasses are biocompatible to tumor and normal cells and that they can promote osteogenic cell proliferation, differentiation, and mineralization. Upon illumination with near-infrared (NIR) light, the bioglass (BG) can efficiently kill bone tumor cells, as demonstrated via in vitro and in vivo experiments. This indicates excellent potential for the integration of multiple functions within the new materials, which will aid in the development and application of novel biomaterials.

Single-frequency fiber lasers have drawn intense attention for their extensive applications from high-resolution spectroscopy and gravitational wave detection to materials processing due to the outstanding properties of low noise, narrow linewidth, and the resulting long coherence length. In this paper, the recent advances of single-frequency fiber oscillators and amplifiers are briefly reviewed in the broad wavelength region of 1–3 μm. Performance improvements in laser noise and linewidth are addressed with the newly developed physical mechanisms. The solution to achieving higher power/energy is also discussed, accompanied by the start-of-the-art results achieved to date.

A compact, low-noise, single-frequency fiber laser by using a newly developed ${\mathrm{Yb}}^{3+}$ heavily doped single-mode phosphate glass fiber has been demonstrated. Over $400\mathrm{mW}$ stable continuous wave single transverse and longitudinal mode laser at $1.06\mathrm{\mu m}$ was achieved from a $0.8\mathrm{cm}$ long active fiber. The measured slope efficiency and estimated quantum efficiency of laser emission are 72.7% and 93%, respectively. The signal-to-noise ratio is higher than $72\mathrm{dB}$, and the linewidth of the fiber laser is less than $7\mathrm{kHz}$, while the measured relative intensity noise is less than $-130\mathrm{dB}/\mathrm{Hz}$ at frequencies of over $1.5\mathrm{MHz}$.

For phosphor-converted white LEDs (pc-WLEDs) based on UV chips, it is essential to search for highly efficient phosphors that have broadly tunable emissions and minimal excitation in the visible range. This would allow the designer of pc-WLEDs to select the desirable emission wavelength and, thereby, fabricate the device with color perception comfortable for the human eye. Conventional rare earth schemes, for instance Ce³⁺ or Eu²⁺ doped phosphors, can be tuned in emission wavelengths, but they cannot overcome the severe intrinsic excitation in the range from blue to green. We report here that Bi³⁺, the valence of which is confirmed by X-ray photoelectron spectra, exhibits almost no excitation in the visible range and has an extremely broad emission covering the full visible spectral range with internal quantum efficiency up to 75% when substituted into the solid solution compounds (Y,Lu,Sc)VO₄:Bi. When the crystal field around Bi³⁺ is tuned by gradual substitution of smaller lanthanide ions for larger lanthanide ions in solid solution, the emission peak position can be modulated linearly between 566 nm and 635 nm due to the susceptibility of bismuth naked 6s electrons to the local environment. In accordance with Rietveld refining results, static and transient photoluminescence spectra reveal the existence of a single type of Bi³⁺ emission center in the sample, and energy transfer from VO₄ ³⁻ group to Bi³⁺ upon excitation into the charge transfer state of VO₄ ³⁻ groups. The mechanism of concentration quenching of Bi³⁺ emission occurs possibly due to dipole–quadrupole rather than exchange interactions. This work shows the potential application of bismuth doped samples in UV converted pc-WLEDs.

We demonstrate a fundamentally mode-locked Yb-fiber laser with 3 GHz repetition rate and $\sim 206\mathrm{fs}$ pulse duration. The laser incorporates two enabling technologies: a 1 cm heavily Yb-doped phosphate glass fiber as the gain medium and a high-dispersion ($-1300{\mathrm{fs}}^2$) output coupler to manage cavity dispersion. The oscillator self-starts and generates up to 53 mW average power.

A novel method to realize high spatial resolution distributed strain measurement is proposed based on phase demodulation scheme of optical frequency domain reflectometry (OFDR). Strain information can be demodulated directly by analyzing the phase change of Rayleigh backscattered light. Strain location can be obtained with high spatial resolution by cross-correlation method using a wide scanning range of tunable laser source. Based on the above scheme, breakpoint detection with 0.1 mm spatial resolution has been demonstrated, static and dynamic strain up to 100 Hz could be distributedly measured with 10 cm spatial resolution over 200 m sensing fiber, and the minimum measurable strain is about 1 με.