Tunable Nd,La:SrF2 laser and passively Q-switched operation based on gold nanobipyramids saturable absorber

A novel Nd, La：SrF_2 disordered crystal is prepared, and its continuous-wave wavelength tuning operation is performed for the first time. Employing a surface plasmon resonance（SPR） based gold nanobipyramids（G-NBPs） saturable absorber,we obtain a compact diode-pumped passively Q-switched Nd, La：SrF_2 laser. The stable Q-switched pulse operates with the shortest pulse duration of 1.15 μs and the maximum repetition rate of 41 k Hz. The corresponding single pulse energy is 2.24 μJ. The results indicate that G-NBPs could be a promising saturable absorber applied to the diode-pumped solid state lasers（DPSSLs）.

Fluorescent polymer-modified gold nanobipyramids for temperature sensing during photothermal therapy in living cells

The temperature monitoring of treated cancer cells is critical in photothermal therapy.Current methods of detecting intracellular temperatures have low accuracy and poor spatial resolution,which limits their application to photothermal therapy.Herein,a strategy for targeted recognition and selective capture of MCF-7 breast cancer cells based on fluorescent polymer poly(N-isopropylacrylamide-benzoxadiazole-2-vinyl-4,4-dimethyl azlactone,PNMV)and modified gold nanobipyramids(Au NBPs-PNMV)was developed for temperature sensing during photothermal therapy.A mucin-1 protein aptamer(Apt)was applied to selectively target mucin-1 protein overexpressed on the surfaces of the MCF-7 cells,which can reduce interference by affinity interaction between the Apt and proteins.During photothermal therapy,the significant Au NBPs photothermal effect increases the fluorescence intensity of PNMV with temperature.Irradiation of MCF-7 cells cultured with Au NBPs-PNMV@Apt by an 808 nm laser increases the temperature of the system,while the cells can be inactivated because of the remarkable Au NBPs-PNMV@Apt photothermal effect.The results indicate that variation in the fluorescence of Au NBPs-PNMV@Apt can be applied as thermometers to monitor the intracellular effect of photothermal therapy.

Active–passive pulse laser based on gold nanobipyramids at 1.3 μm wavelength

Two-dimensional(2 D) materials have attracted intense attention in photonics and optoelectronics for their excellent nonlinear characteristics and are applied for the generation of laser pulses. Here, an active–passive Nd:GdVO_4 1.3 μm laser is realized by using an acousto-optic modulator and gold nanobipyramids absorber.The pulse width of 150.5 ns is obtained in the doubly Q-switched laser. The compression ratio and enhancement time are 82.6% and 16. The doubly Q-switched technology compresses the pulse width, improves the peak power,and stabilizes the pulse, illustrating that double modulation technology opens the door of controllable ultrafast lasers based on 2 D materials.

Antiangiogenesis-Combined Photothermal Therapy in the Second Near-Infrared Window at Laser Powers Below the Skin Tolerance Threshold

Photothermal agents with strong light absorption in the second near-infrared(NIR-II)region(1000-1350 nm)are strongly desired for successful photothermal therapy(PTT).In this work,titania-coated Au nanobipyramids(NBP@TiO2)with a strong plasmon resonance in the NIR-II window were synthesized.The NBP@TiO2 nanostructures have a high photothermal conversion efficiency of(93.3±5.2)%under 1064-nm laser irradiation.They are also capable for loading an anticancer drug combretastatin A-4 phosphate(CA4P).In vitro PTT studies reveal that 1064-nm laser irradiation can efficiently ablate human lung cancer A549 cells and enhance the anticancer effect of CA4P.Moreover,the CA4P-loaded NBP@TiO2 nanostructures combined with PTT induce a synergistic antiangiogenesis effect.In vivo studies show that such CA4Ploaded NBP@TiO2 nanostructures under mild 1064-nm laser irradiation at an optical power density of 0.4 W cm?2,which is lower than the skin tolerance threshold value,exhibit a superior antitumor effect.This work presents not only the development of the NBP@TiO2 nanostructures as a novel photothermal agent responsive in the NIR-II window but also a unique combined chemo-photothermal therapy strategy for cancer therapy.